Class 10 Question Paper 2025 Science

ANNUAL EXAMINATION

Question Paper
2025
NCERT BASED SYLLABUS

FOR CBSE AND STATE BOARD
FOLLOWING NCERT

KVS QUESTION PAPERS

*ECNEICS*
Series : 1GEFH SET~1
प्रश्न-पत्र कोड
Q.P. Code 31/1/1
रोि नं. परीक्षार्थी प्रश्न-पत्र कोड को उत्तर-पस्ु तिका के
Roll No. मख
ु -पृष्ठ पर अवश्य स्िखें ।
Candidates must write the Q.P. Code
on the title page of the answer-book.

नोट NOTE

(I) कृ पया जााँच कर िें स्क इस प्रश्न-पत्र में मस्ु िि पृष्ठ (I) Please check that this question paper
27 हैं । contains 27 printed pages.

(II) प्रश्न-पत्र में दास्हने हार्थ की ओर स्दए गए (II) Q.P. Code given on the right hand
प्रश्न-पत्र कोड को परीक्षार्थी उत्तर-पस्ु तिका के side of the question paper should be
written on the title page of the
मख ु -पृष्ठ पर स्िखें । answer-book by the candidate.

(III) कृ पया जााँच कर िें स्क इस प्रश्न-पत्र में 39 प्रश्न (III) Please check that this question paper
हैं । contains 39 questions.

(IV) कृपया प्रश्न का उत्तर लिखना शुरू करने से (IV) Please write down the Serial
पहिे, उत्तर-पुलतिका में यथा तथान पर प्रश्न Number of the question in the
answer-book at the given place
का क्रमाांक अवश्य लिखें । before attempting it.
(V) इस प्रश्न-पत्र को पढ़ने के स्िए 15 स्मनट का (V) 15 minute time has been allotted to
समय स्दया गया है । प्रश्न-पत्र का स्विरण पवू ााह्न read this question paper. The
question paper will be distributed
में 10.15 बजे स्कया जाएगा । 10.15 बजे से at 10.15 a.m. From 10.15 a.m. to
10.30 बजे िक परीक्षार्थी के वि प्रश्न-पत्र को 10.30 a.m., the candidates will
पढ़ेंगे और इस अवस्ि के दौरान वे उत्तर-पस्ु तिका read the question paper only and
पर कोई उत्तर नहीं स्िखेंगे । will not write any answer on the
# answer-book during this period.

विज्ञान
SCIENCE

निर्धारित समय : 3 घण्टे अनर्कतम अंक : 80
Time allowed : 3 hours Maximum Marks : 80

*31/1/1* 1 # [ P.T.O. ]

*ECNEICS*
सामान्‍य‍न ‍र्देश‍:
निम्िन न त निर्देशों को बहुत सधवर्धिी से पऩिए औि उिकध सख़्ती से पध ि कीनिए :
(i) इस प्रश्ि-पत्र में कु 39 प्रश्ि हैं । सभी‍प्रश्ि अन वायय हैं ।

(ii) यह प्रश्ि-पत्र पााँच ण्डों में नवभधनित नकयध गयध है – क,‍ख,‍ग,‍घ एवं ङ ।
(iii) खण्‍ड‍क – प्रश्ि संख्यध 1‍से 20 तक बहुनवकल्पीय प्रकधि के प्रश्ि हैं । प्रत्येक प्रश्ि 1 अंक कध है ।
(iv) खण्‍ड‍ख – प्रश्ि संख्यध 21‍से 26 तक अनत घ-ु उत्तिीय प्रकधि के प्रश्ि हैं । प्रत्येक प्रश्ि 2 अंकों कध
है । इि प्रश्िों के उत्ति 30 से 50 शब्र्दों में नर्दए िधिे चधनहए ।
(v) खण्‍ड‍ग – प्रश्ि संख्यध 27 से 33 तक घु-उत्तिीय प्रकधि के प्रश्ि हैं । प्रत्येक प्रश्ि 3 अंकों कध है । इि
प्रश्िों के उत्ति 50 से 80 शब्र्दों में नर्दए िधिे चधनहए ।
(vi) खण्‍ड‍घ – प्रश्ि सख्ं यध 34 से 36 तक र्दीघा-उत्तिीय प्रकधि के प्रश्ि हैं । प्रत्येक प्रश्ि 5 अक
ं ों कध है ।
इि प्रश्िों के उत्ति 80 से 120 शब्र्दों में नर्दए िधिे चधनहए ।
(vii) खण्‍ड‍ ङ – प्रश्ि संख्यध 37 से 39 तक 3 स्रोत-आर्धरित/प्रकिण-आर्धरित इकधइयों के मूल्यधंकि के
4 अंकों के प्रश्ि (उप-प्रश्िों सनहत) हैं ।

(viii) प्रश्ि-पत्र में समग्र नवकल्प िहीं नर्दयध गयध है । यद्यनप, कुछ ण्डों में आंतरिक नवकल्प नर्दए गए हैं । इस प्रकधि
के प्रश्िों में के व एक ही नवकल्प कध उत्ति र्दीनिए ।

खण्ड क $

प्रश्ि संख्यध 1 से 20 तक के प्रत्येक प्रश्ि में नर्दए गए चधि नवकल्पों में से सबसे उनचत नवकल्प चनु िए औि
न न ए । ग़ त उत्ति के न ए कोई ॠणधत्मक अक ं ि िहीं है । 201=20

1. जि का स्वद्यिु -अपघटन एक स्वयोजन (अपघटन) अस्िस्िया है । जि के स्वद्यिु -अपघटन के समय
इिेक्ट्रोडों पर मक्ट्ु ि गैसों – हाइड्रोजन और ऑक्ट्सीजन के िव्यमानों का अनपु ाि (MH : MO) होिा
है :
(A) 8:1 (B) 2:1
(C) 1:2 (D) 1:8

2. वायु की उपस्तर्थस्ि में ऐिस्ु मस्नयम और मैग्नीस्ियम के दहन होने पर बनने वािे उत्पाद िमि: हैं :
(A) Al3O4 और MgO2 (B) Al2O3 और MgO

(C) Al3O4 और MgO (D) Al2O3 और MgO2

*31/1/1* 2 #

*ECNEICS*
General Instructions :
Read the following instructions very carefully and strictly follow them :
(i) This question paper comprises 39 questions. All questions are compulsory.
(ii) This question paper is divided into five sections – A, B, C, D and E.
(iii) Section A – Questions No. 1 to 20 are Multiple Choice Questions. Each
question carries 1 mark.
(iv) Section B – Questions No. 21 to 26 are Very Short Answer type questions.
Each question carries 2 marks. Answer to these questions should be in the
range of 30 to 50 words.
(v) Section C – Questions No. 27 to 33 are Short Answer type questions. Each
question carries 3 marks. Answer to these questions should in the range of
50 to 80 words.
(vi) Section D – Questions No. 34 to 36 are Long Answer type questions. Each
question carries 5 marks. Answer to these questions should be in the range of
80 to 120 words.
(vii) Section E – Questions No. 37 to 39 are of 3 source-based/case-based units of
assessment carrying 4 marks each with sub-parts.
(viii) There is no overall choice. However, an internal choice has been provided in
some sections. Only one of the alternatives has to be attempted in such
questions.

SECTION A

Select and write the most appropriate option out of the four options given for
each of the questions no. 1 to 20. There is no negative marking for incorrect
response. 201=20

1. Electrolysis of water is a decomposition reaction. The mass ratio
(MH : MO) of hydrogen and oxygen gases liberated at the electrodes
during electrolysis of water is :
(A) 8:1 (B) 2:1
(C) 1:2 (D) 1:8

2. The products formed when Aluminium and Magnesium are burnt in the
presence of air respectively are :
(A) Al3O4 and MgO2 (B) Al2O3 and MgO
(C) Al3O4 and MgO (D) Al2O3 and MgO2

*31/1/1* 3 # [ P.T.O. ]

*ECNEICS*
3. स्नम्नस्िस्खि िास्िका में pH तके ि पर चार स्वियनों A, B, C और D के pH मान दिााए गए हैं :

B C

 
1 2 3 4 5 6 7 8 9 10 11 12 13 14
 
D A

ये चारों स्वियन A, B, C और D िमि: हैं
(A) प्रबि अम्ि, दबु ाि अम्ि, उदासीन, प्रबि क्षारक
(B) दबु ाि अम्ि, उदासीन, दबु ाि क्षारक, प्रबि क्षारक
(C) दबु ाि अम्ि, उदासीन, प्रबि क्षारक, दबु ाि क्षारक
(D) दबु ाि अम्ि, उदासीन, प्रबि क्षारक, प्रबि अम्ि
4. स्नम्नस्िस्खि अस्िस्ियाओ ं पर स्वचार कीस्जए :
(i) िनु हाइड्रोक्ट्िोररक अम्ि, सोस्डयम हाइड्रॉक्ट्साइड से अस्िस्िया करिा है ।
(ii) मैग्नीस्ियम ऑक्ट्साइड, िनु हाइड्रोक्ट्िोररक अम्ि से अस्िस्िया करिा है ।
(iii) काबान डाइऑक्ट्साइड, सोस्डयम हाइड्रॉक्ट्साइड से अस्िस्िया करिी है ।
यह पाया जािा है स्क प्रत्येक प्रकरण में :
(A) िवण और जि बनिा है ।
(B) उदासीन िवण बनिे हैं ।
(C) हाइड्रोजन गैस बनिी है ।
(D) अम्िीय िवण बनिे हैं ।
5. दो ित्त्वों A और B के बीच अस्िस्िया से कोई यौस्गक C बनिा है । A इिेक्ट्रॉन खोिा है िर्था B
इिेक्ट्रॉन ग्रहण करिा है । यौस्गक C स्नम्नस्िस्खि में से कौन-सा एक गणु हीं‍दिााएगा ?
(A) इसका गिनांक उच्च है ।
(B) यह जि में अत्यस्िक स्विेय है ।
(C) इसके स्वजािीय (स्वपरीि आवेस्िि) आयनों के बीच दबु ाि स्तर्थर-वैद्यिु आकर्ाण बि है ।
(D) यह अपनी गस्िि अवतर्था अर्थवा जिीय स्वियन में स्वद्यिु चािन करिा है ।
*31/1/1* 4 #

*ECNEICS*
3. The following table shows the pH values of four solutions A, B, C and D
on a pH scale :
B C

 
1 2 3 4 5 6 7 8 9 10 11 12 13 14
 
D A

The solutions A, B, C and D respectively are of a
(A) Strong acid, weak acid, neutral, strong base
(B) Weak acid, neutral, weak base, strong base
(C) Weak acid, neutral, strong base, weak base
(D) Weak acid, neutral, strong base, strong acid

4. Consider the following reactions :
(i) Dilute hydrochloric acid reacts with sodium hydroxide.
(ii) Magnesium oxide reacts with dilute hydrochloric acid.
(iii) Carbon dioxide reacts with sodium hydroxide.
It is found that in each case :
(A) Salt and water is formed.
(B) Neutral salts are formed.
(C) Hydrogen gas is formed.
(D) Acidic salts are formed.

5. Reaction between two elements A and B, forms a compound C. A loses
electrons and B gains electrons. Which one of the following properties
will not be shown by compound C ?
(A) It has high melting point.
(B) It is highly soluble in water.
(C) It has weak electrostatic forces of attraction between its oppositely
charged ions.
(D) It conducts electricity in its molten state or aqueous solution.

*31/1/1* 5 # [ P.T.O. ]

*ECNEICS*
6. स्वद्यिु -अपघटनी अपचयन प्रस्िया द्वारा गस्िि क्ट्िोराइडों से प्राप्त होने वािी िािएु ाँ हैं :
(A) गोल्ड और स्सल्वर
(B) कै स्ल्ियम और मैग्नीस्ियम
(C) ऐिस्ु मस्नयम और स्सल्वर
(D) सोस्डयम और आयरन

7. नीचे स्दए गए स्कस स्वकल्प में मैग्नीस्ियम ऑक्ट्साइड बनना सही स्दखाया गया है ?

8. माँहु में िार का कम मात्रा में स्रास्वि होना स्कस पररविान को प्रिास्वि करिा है ?
(A) प्रोटीनों से ऐमीनो अम्ि
(B) वसा से वसीय अम्ि और स्ग्िसरॉि
(C) तटाचा से सरि िका रा
(D) िका रा से ऐल्कोहॉि

9. वह कौन-सा पादप हॉमोन है स्जसकी सांििा, प्ररोह के प्रकाि से दरू वािे िाग की कोस्िकाओ ं को
िम्बाई में वृस्ि के स्िए उद्दीस्पि करिी है ?
(A) साइटोकाइस्नन
(B) स्जब्बेरेस्िन
(C) ऐस्ड्रनिीन
(D) ऑस्क्ट्सन

*31/1/1* 6 #

*ECNEICS*
6. The metals obtained from their molten chlorides by the process of
electrolytic reduction are :
(A) Gold and silver
(B) Calcium and magnesium
(C) Aluminium and silver
(D) Sodium and iron

7. The formation of magnesium oxide is correctly shown in option :

8. Secretion of less saliva in mouth will effect the conversion of :
(A) proteins into amino acids
(B) fats into fatty acids and glycerol
(C) starch into simple sugars
(D) sugars into alcohol

9. The plant hormone whose concentration stimulates the cells to grow
longer on the side of the shoot which is away from light is :
(A) Cytokinins
(B) Gibberellins
(C) Adrenaline
(D) Auxins

*31/1/1* 7 # [ P.T.O. ]

*ECNEICS*
10. उियस्िंगी पष्ु प के स्वर्य में सही कर्थन है/हैं :
(i) इनमें पक ंु े सर और तत्रीके सर दोनों होिे हैं ।
(ii) इनमें या िो पक ंु े सर होिा है अर्थवा तत्रीके सर होिा है ।
(iii) ये या िो तवपरागण दिाािे हैं अर्थवा परपरागण दिाािे हैं ।
(iv) ये अपने आप फि उत्पन्न नहीं कर सकिे हैं ।
(A) के वि (i) (B) के वि (iv)
(C) (i) और (iii) (D) (i) और (iv)

11. गोि और हरे (RRyy) बीजों वािे मटर के पौिों का झरु ीदार और पीिे (rrYY) बीजों वािे मटर के
पौिों के सार्थ संकरण कराया गया । F1 संिस्ि के पौिों द्वारा स्वकस्सि बीज होंगे :
(A) 50% गोि और हरे (B) 75% झरु ीदार और हरे
(C) 100% गोि और पीिे (D) 75% झरु ीदार और पीिे

12. स्नम्नस्िस्खि ग्िक
ू ोज़ के स्वखण्डन का पर्थ दिााया गया है :
(a) (b)
ू ोज़ ⎯⎯⎯
ग्िक → पायरुवेट + ऊजाा ⎯⎯⎯ → िैस्क्ट्टक अम्ि + ऊजाा

तर्थि ‘a’ और ‘b’ िमि: हैं :
(A) माइटोकॉस्न्ड्रया और ऑक्ट्सीजन के अिाव वािी पेिीय कोस्िकाएाँ
(B) कोस्िकािव्य और ऑक्ट्सीजन प्रचरु पेिीय कोस्िकाएाँ
(C) कोस्िकािव्य और यीतट कोस्िकाएाँ
(D) कोस्िकािव्य और ऑक्ट्सीजन के अिाव वािी पेिीय कोस्िकाएाँ
13. दपाण ‘X’ सयू ा के प्रकाि को सौर िट्टी में सांस्िि करिा है िर्था दपाण ‘Y’ वाहनों के पाश्वा में ड्राइवरों को
पीछे के रैस्फक को देखने के स्िए िगाया जािा है । इन दो दपाणों के स्वर्य में स्नम्नस्िस्खि में से
कौन-से कर्थन सही हैं ?
(i) दपाण ‘X’ द्वारा बना प्रस्िस्बम्ब वातिस्वक, छोटा और इसके फोकस पर होिा है ।
(ii) दपाण ‘Y’ द्वारा बना प्रस्िस्बम्ब आिासी, छोटा और सीिा होिा है ।
(iii) दपाण ‘X’ द्वारा बना प्रस्िस्बम्ब आिासी, छोटा और सीिा होिा है ।
(iv) दपाण ‘Y’ द्वारा बना प्रस्िस्बम्ब वातिस्वक, छोटा और इसके फोकस पर होिा है ।
(A) (i) और (ii) (B) (ii) और (iii)
(C) (iii) और (iv) (D) (i) और (iv)

*31/1/1* 8 #

*ECNEICS*
10. The correct/true statement(s) for a bisexual flower is/are :
(i) They possess both stamen and pistil.
(ii) They possess either stamen or pistil.
(iii) They exhibit either self-pollination or cross-pollination.
(iv) They cannot produce fruits on their own.
(A) (i) only (B) (iv) only
(C) (i) and (iii) (D) (i) and (iv)

11. If pea plants with round and green seeds (RRyy) are crossed with pea
plants having wrinkled and yellow seeds (rrYY), the seeds developed by
the plants of F1 generation will be :
(A) 50% round and green (B) 75% wrinkled and green
(C) 100% round and yellow (D) 75% wrinkled and yellow

12. The breakdown of glucose has taken the following pathway :
(a) (b)
→ Pyruvate + Energy ⎯⎯⎯
Glucose ⎯⎯⎯ → Lactic acid + Energy
The sites ‘a’ and ‘b’ respectively are :
(A) Mitochondria and Oxygen deficient muscle cells
(B) Cytoplasm and Oxygen rich muscle cells
(C) Cytoplasm and Yeast cells
(D) Cytoplasm and Oxygen deficient muscle cells

13. Mirror ‘X’ is used to concentrate sunlight in solar furnace and Mirror ‘Y’
is fitted on the side of the vehicle to see the traffic behind the driver.
Which of the following statements are true for the two mirrors ?
(i) The image formed by mirror ‘X’ is real, diminished and at its focus.
(ii) The image formed by mirror ‘Y’ is virtual, diminished and erect.
(iii) The image formed by mirror ‘X’ is virtual, diminished and erect.
(iv) The image formed by mirror ‘Y’ is real, diminished and at its focus.
(A) (i) and (ii) (B) (ii) and (iii)
(C) (iii) and (iv) (D) (i) and (iv)

*31/1/1* 9 # [ P.T.O. ]

*ECNEICS*
14. कोई वृि व्यस्ि पक्ष्मािी पेस्ियों की दबु ाििा िर्था अस्िनेत्र िेंस के िचीिेपन में कमी होने के कारण
दृस्िदोर् से पीस़्िि है । यस्द यह दृस्िदोर् ‘a’ है स्जसका संिोिन िेंस ‘b’ द्वारा स्कया जा सकिा है, िो
‘a’ और ‘b’ िमि: हैं :
(A) दीघा दृस्ि दोर् और उत्ति िेंस
(B) जरा दरू दृस्ििा और स्द्वफोकसी िेंस
(C) स्नकट दृस्ि दोर् और अविि िेंस
(D) स्नकट दृस्ि दोर् और स्द्वफोकसी िेंस
15. स्नम्नस्िस्खि में से कौन-कौन से समहू कोई आहार श्ृंखिा हीं‍बनािे हैं ?
(i) िेस़्िया, खरगोि, घास, िेर
(ii) प्िवक, मानव, स्टड्डा, मछिी
(iii) बाज़, घास, सपा, स्टड्डा, मेंढक
(iv) घास, सपा, िेस़्िया, बाघ
(A) (i) और (iv) (B) (i) और (iii)
(C) (ii) और (iii) (D) (ii) और (iv)

16. स्कसी तर्थिीय पाररिंत्र में हरे पादपों की पस्त्तयों द्वारा प्राप्त सौर ऊजाा का िगिग स्किने प्रस्ििि िाग
खाद्य ऊजाा में पररवस्िाि हीं होिा है ?
(A) 1% (B) 10%
(C) 90% (D) 99%

प्रश्‍ ‍संख्य‍ ा‍17 से‍20 के ‍निए, र्दो‍कथ ‍नर्दए‍गए‍हैं‍–‍नि में‍एक‍को‍अनभकथ ‍ (A) तथा‍र्दूसरे‍को‍
कारण‍ (R) द्वारा‍अंनकत‍नकया‍गया‍है‍ ।‍इ ‍प्रश्‍ ों‍के ‍सही‍उत्तर‍ ीचे‍ नर्दए‍गए‍कोडों‍ (A), (B), (C)
और‍(D) में‍से‍चु कर‍र्दीनिए‍।
(A) अस्िकर्थन (A) और कारण (R) दोनों सही हैं और कारण (R), अस्िकर्थन (A) की सही
व्याख्या करिा है ।
(B) अस्िकर्थन (A) और कारण (R) दोनों सही हैं, परन्िु कारण (R), अस्िकर्थन (A) की
सही व्याख्या हीं करिा है ।
(C) अस्िकर्थन (A) सही है, परन्िु कारण (R) ग़िि है ।
(D) अस्िकर्थन (A) ग़िि है, परन्िु कारण (R) सही है ।
17. अनभकथि (A) : अपघटन अस्िस्ियाएाँ सामान्यिः ऊष्मािोर्ी अस्िस्ियाएाँ होिी हैं ।
कधिण (R) : काबास्नक पदार्था का कम्पोतट में अपघटन ऊष्माक्षेपी प्रस्िया/अस्िस्िया है ।
*31/1/1* 10 #

*ECNEICS*
14. An old person is suffering from an eye defect caused by weakening of
ciliary muscles and diminishing flexibility of the eye lens. If the defect of
vision is ‘a’ which can be corrected by lens ‘b’, then ‘a’ and ‘b’ respectively
are :
(A) hypermetropia and convex lens
(B) presbyopia and bifocal lens
(C) myopia and concave lens
(D) myopia and bifocal lens

15. Which of the following groups do not constitute a food chain ?
(i) Wolf, rabbit, grass, lion
(ii) Plankton, man, grasshopper, fish
(iii) Hawk, grass, snake, grasshopper, frog
(iv) Grass, snake, wolf, tiger
(A) (i) and (iv) (B) (i) and (iii)
(C) (ii) and (iii) (D) (ii) and (iv)

16. The percentage of solar energy which is not converted into food energy by
the leaves of green plants in a terrestrial ecosystem is about :
(A) 1% (B) 10%
(C) 90% (D) 99%

For Questions number 17 to 20, two statements are given — one labelled as
Assertion (A) and the other labelled as Reason (R). Select the correct
answer to these questions from the codes (A), (B), (C) and (D) as given
below.
(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the
correct explanation of Assertion (A).
(B) Both Assertion (A) and Reason (R) are true, but Reason (R) is not
the correct explanation of Assertion (A).
(C) Assertion (A) is true, but Reason (R) is false.
(D) Assertion (A) is false, but Reason (R) is true.

17. Assertion (A) : Decomposition reactions are generally endothermic
reactions.
Reason (R) : Decomposition of organic matter into compost is an
exothermic process.
*31/1/1* 11 # [ P.T.O. ]

*ECNEICS*
18. अनभकथि (A) : मानव संिान में मानवों के सिी आिारििू िक्षण होिे हैं ।
कधिण (R) : मानव संिान बहुि कम स्वस्िन्निाएाँ दिाािे हुए िथ्यि: अपने मािा-स्पिा जैसी ही
स्दखाई देिी है ।
19. अनभकथि (A) : दो चम्ु बकीय क्षेत्र रे खाएाँ परतपर एक-दसू रे का प्रस्िच्छे दन नहीं करिी हैं ।
कधिण (R) : स्दक् सचू क सईु दो चम्ु बकीय क्षेत्र रे खाओ ं के प्रस्िच्छे दन स्बन्दु पर दो स्दिाओ ं की
ओर संकेि नहीं कर सकिी है ।
20. अनभकथि (A) : 1980 से वायमु ंडि में ओज़ोन की मात्रा में िीव्रिा से स्गरावट आने िगी ।
कधिण (R) : ऑक्ट्सीजन के परमाण,ु ऑक्ट्सीजन के अणओ ु ं से संयि ु होकर ओज़ोन बनािे हैं ।
खण्ड ख
प्रश्ि सख्ं यध 21 से 26 अनत घ-ु उत्तिीय प्रकधि के प्रश्ि हैं ।
21. कोई छात्र अपने स्वद्यािय की प्रयोगिािा में स्नम्नस्िस्खि प्रयोग करिा है ।

ऐसे दो प्रेक्षणों की सचू ी बनाइए जो यह पस्ु ि करिे हैं स्क इस प्रयोग में कोई रासायस्नक पररविान हुआ
है । 2

22. नामास्ं कि आरे ख खींचकर हधइड्रध में मक
ु ु िन के स्वस्िन्न चरण दिााइए । 2

23. (क) रुस्िर की हास्न कम-से-कम होने के अस्िररि स्कसी वास्हनी से रिस्राव को अवरुि करना
(रोकना) क्ट्यों अस्नवाया है ? रुस्िर के उस संघटक का नाम स्िस्खए जो इस प्रस्िया में सहायिा
करिा है िर्था उल्िेख कीस्जए स्क इस सघं टक द्वारा इस काया का सम्पादन स्कस प्रकार स्कया
जािा है । 2
अथवा
(ख) (i) पादपों की वहन िंत्र प्रणािी जन्िओ ु ं की अपेक्षा िीमी होिी है । कारण दीस्जए ।
(ii) पादपों में पदार्थों के तर्थानान्िरण/पररवहन में फ़्िोएम की िस्ू मका का उल्िेख
कीस्जए । 2

*31/1/1* 12 #

*ECNEICS*
18. Assertion (A) : A human child bears all the basic features of human
beings.
Reason (R) : It looks exactly like its parents, showing very little
variations.
19. Assertion (A) : No two magnetic field lines are found to cross each other.
Reason (R) : The compass needle cannot point towards two directions
at the point of intersection of two magnetic field lines.
20. Assertion (A) : The amount of ozone in the atmosphere began to drop
sharply in the 1980s.
Reason (R) : The oxygen atoms combine with molecular oxygen to form
ozone.

SECTION B
Questions no. 21 to 26 are Very Short Answer Type questions.
21. A student performs the following experiment in his school laboratory.

List two observations to justify that in this experiment a chemical change
has taken place. 2
22. Draw labelled diagrams to show different stages of budding in Hydra. 2
23. (a) Besides minimising the loss of blood, why is it essential to plug any
leak in a blood vessel ? Name the component of blood which helps
in this process and state how this component perform this
function. 2
OR
(b) (i) The transport system in plants is relatively slower than in
animals. Give reasons.
(ii) State the role of phloem in the transport of materials in
plants. 2
*31/1/1* 13 # [ P.T.O. ]

*ECNEICS*
24. कोई स्बम्ब 30 cm फोकस दरू ी के स्कसी अविि िेंस से 60 cm दरू ी पर स्तर्थि है । िेंस सत्रू का
उपयोग करके इस प्रकरण में प्रस्िस्बम्ब की स्तर्थस्ि ज्ञाि कीस्जए । 2

25. (क) प्रस्िरोि R के स्कसी िार को िीन बराबर िागों में काटा गया है । यस्द इन िीनों िागों को
पाश्वािम में संयोस्जि स्कया गया है, िो इस संयोजन का कुि प्रस्िरोि पररकस्िि कीस्जए । 2

अथवा
(ख) स्वद्यिु िस्ि की पररिार्ा स्िस्खए । हम यह कब कहिे हैं स्क स्कसी स्वद्यिु पररपर्थ में उपिि
ु
िस्ि 1 वाट है ? 2

26. ‘‘कृ स्र् में रसायनों और पी़िकनास्ियों का अत्यस्िक उपयोग पयाावरण पर दष्ु प्रिाव डाििा है ।’’ इस
कर्थन की पस्ु ि कीस्जए । 2

खण्ड ग

प्रश्ि संख्यध 27 से 33 घु-उत्तिीय प्रकधि के प्रश्ि हैं ।

27. (क) ‘‘सस्ियिा श्ेणी में मध्य की िािओ ु ं के स्नष्कर्ाण में िी स्वतर्थापन अस्िस्ियाओ ं की मुख्य
िस्ू मका होिी है ।’’ दो उदाहरण देकर इस कर्थन की पस्ु ि कीस्जए ।
(ख) सस्ियिा श्ेणी में सबसे ऊपर स्तर्थि िािओ ु ं को उनके ऑक्ट्साइडों को काबान द्वारा अपचस्यि
करके प्राप्त क्ट्यों नहीं स्कया जा सकिा है ? 3

28. (क) स्कसी स्ियाकिाप की सहायिा से उन पररस्तर्थस्ियों की व्याख्या कीस्जए स्जनमें िोहे
(आयरन) की वतिुओ ं पर जंग िगिी है । 3

अथवा
(ख) (i) उन दो िािओ ु ं के नाम स्िस्खए जो ठंडे जि के सार्थ िीक्ष्णिा से अस्िस्िया करिी
हैं । उन िीन प्रेक्षणों की सचू ी बनाइए स्जन्हें कोई छात्र इन िािओ
ु ं को जि से िरे
बीकर में डािने पर नोट करे गा ।
(ii) इन िािओ
ु ं की जि के सार्थ अस्िस्िया में स्नकिने वािी गैस (यस्द कोई है) की
पहचान के स्िए कोई परीक्षण स्िस्खए । 3

*31/1/1* 14 #

*ECNEICS*
24. An object is placed at a distance of 60 cm from a concave lens of focal
length 30 cm. Use lens formula to find the position of the image formed in
this case. 2

25. (a) A wire of resistance R is cut into three equal parts. If these three
parts are then joined in parallel, calculate the total resistance of
the combination so formed. 2
OR

(b) Define electric power. When do we say that the power consumed in
an electric circuit is 1 watt ? 2

26. ‘‘Excessive use of chemicals and pesticides in agriculture adversely effect
the environment.’’ Justify this statement. 2

SECTION C

Questions no. 27 to 33 are Short Answer Type questions.

27. (a) ‘‘Displacement reactions also play a key role in extracting metals
in the middle of the reactivity series.’’ Justify this statement with
two examples.

(b) Why can metals high up in the reactivity series not be obtained by
reduction of their oxides by carbon ? 3

28. (a) With the help of an activity, explain the conditions under which
iron articles get rusted. 3

OR

(b) (i) Name two metals which react violently with cold water. List
any three observations which a student notes when these
metal are dropped in a beaker containing water.

(ii) Write a test to identify the gas evolved (if any) during the
reaction of these metals with water. 3

*31/1/1* 15 # [ P.T.O. ]

*ECNEICS*
29. पादपों में न िो िंस्त्रका िंत्र होिा है और न ही पेस्ियााँ होिी हैं स्फर िी वे उद्दीपन से अनस्ु िया करिे हैं ।
उदाहरण के स्िए छुई-मुई के पौिे की पस्त्तयााँ तपिा स्कए जाने पर म़िु कर मरु झा जािी हैं ।
(क) “छुई-मईु ” के पौिों में सचू ना का सचं रण स्कस प्रकार होिा है ?
(ख) पादप कोस्िकाओ ं को दिानीय अनस्ु िया करने योग्य कौन बनािा है ?
(ग) उपयाि
ु उस्ल्िस्खि गस्ि और मटर के पौिे के प्रिानों की गस्ि के बीच अन्िर तपि कीस्जए । 3

30. (क) गणु सत्रू क्ट्या होिे हैं ?
(ख) व्याख्या कीस्जए स्क िैंस्गक जनन करने वािे जीवों की तपीिीज़ में DNA की मात्रा का
तर्थास्यत्व स्कस प्रकार सस्ु नस्श्चि होिा है । 3

31. स्कसी उत्ति दपाण द्वारा बनने वािे प्रस्िस्बम्ब की प्रकृ स्ि, स्तर्थस्ि और सापेक्ष साइज़ को दिााने के स्िए
उस प्रकरण में स्करण आरे ख खींस्चए स्जसमें स्बम्ब (i) अनन्ि पर स्तर्थि है िर्था (ii) दपाण के ध्रवु P
और अनन्ि के बीच स्तर्थि है । 3

32. स्नम्नस्िस्खि स्वद्यिु पररपर्थ पर स्वचार कीस्जए :

स्नम्नस्िस्खि के मान पररकस्िि कीस्जए : 3
(क) पररपर्थ का कुि प्रस्िरोि
(ख) स्वद्यिु स्रोि से िी गई कुि िारा
(ग) 10  और 15  प्रस्िरोिकों के पाश्वािम संयोजन के स्सरों पर स्विवान्िर

*31/1/1* 16 #

*ECNEICS*
29. Plants have neither a nervous system nor muscles, even then they
respond to stimuli. For example, the leaves of chhui-mui (touch-me-not)
plant when touched begin to fold up and droop.

(a) How is the information communicated in ‘‘touch-me-not’’ plants ?
(b) What enables the plant cells to bring out the observable response ?
(c) Differentiate the movement mentioned above from the movement
of tendrils in a pea plant. 3

30. (a) What are chromosomes ?
(b) Explain in brief how stability of DNA content of a species is
ensured in sexually reproducing organisms ? 3

31. Draw ray diagrams to show the nature, position and relative size of the
image formed by a convex mirror when the object is placed (i) at infinity
and (ii) between infinity and pole P of the mirror. 3

32. Consider the following electric circuit :

Calculate the values of the following : 3
(a) The total resistance of the circuit
(b) The total current drawn from the source
(c) Potential difference across the parallel combination of 10  and
15  resistors

*31/1/1* 17 # [ P.T.O. ]

*ECNEICS*
33. (क) िम्बाई l और अनप्रु तर्थ-काट क्षेत्रफि A के स्कसी बेिनाकार चािक के प्रस्िरोि और उसकी
प्रस्िरोिकिा के बीच संबंि स्िस्खए । इस संबंि का उपयोग करके प्रस्िरोिकिा का SI मात्रक
व्यत्ु पन्न कीस्जए ।
(ख) स्वद्यिु िापन यस्ु ियों में स्मश्ािओ
ु ं का उपयोग क्ट्यों स्कया जािा है ? 3

खण्ड घ
प्रश्ि संख्यध 34 से 36 र्दीघा-उत्तिीय प्रकधि के प्रश्ि हैं ।

34. (क) (i) ब्यटू ीन (C4H8) की दो समावयवी संरचनाएाँ खींस्चए ।

(ii) स्नम्नस्िस्खि यौस्गकों के नाम स्िस्खए :
H H H
  
(I) H – C – C – C – Cl
  
H H H

H H H
  
(II) H– C – C – C – C – H
   
H H O H

(iii) स्नम्नस्िस्खि अस्िस्ियाओ ं के रासायस्नक समीकरण स्िस्खए िर्था प्रत्येक प्रकरण में
अस्िस्िया होने के स्िए आवश्यक एक ििा/पररस्तर्थस्ि का उल्िेख िी कीस्जए ।
(I) एर्थेनॉि का पणू ा ऑक्ट्सीकरण
(II) प्रोपीन का हाइड्रोजनीकरण
(III) एर्थेनॉइक अम्ि की एर्थेनॉि से अस्िस्िया 5
अथवा
(ख) (i) कोई काबान यौस्गक X अच्छा स्विायक है । सोस्डयम से अस्िस्िया करके , X दो
उत्पाद Y और Z बनािा है । Z का उपयोग वनतपस्ि िेि को वनतपस्ि घी में
पररवस्िाि करने में स्कया जािा है । X, Y और Z को पहचास्नए और इनके नाम
स्िस्खए । अपने उत्तर की पस्ु ि के स्िए X की सोस्डयम से अस्िस्िया का समीकरण
िी स्िस्खए ।
*31/1/1* 18 #

*ECNEICS*
33. (a) Write the relationship between resistivity and resistance of a
cylindrical conductor of length l and area of cross-section A. Hence
derive the SI unit of resistivity.

(b) Why are alloys used in electrical heating devices ? 3

SECTION D

Questions no. 34 to 36 are Long Answer Type questions.

34. (a) (i) Draw two isomeric structures of Butene (C4H8).

(ii) Name the following compounds :
H H H
  
(I) H – C – C – C – Cl
  
H H H

H H H
  
(II) H– C – C – C – C – H
   
H H O H
(iii) Write the chemical equations for the following reactions.
Mention one essential condition each for these reactions to
take place.
(I) Ethanol undergoes complete oxidation
(II) Propene undergoes hydrogenation
(III) Ethanoic acid reacts with ethanol 5

OR
(b) (i) A carbon compound X is a good solvent. On reaction with
sodium, X forms two products Y and Z. Z is used to convert
vegetable oil into vegetable ghee. Identify and name X, Y
and Z. Also write the equation of reaction of X with sodium
to justify your answer.

*31/1/1* 19 # [ P.T.O. ]

*ECNEICS*
(ii) यह दिााने के स्िए रासायस्नक समीकरण स्िस्खए स्क क्ट्या होिा है जब :
(I) एर्थेनॉि का ऑक्ट्सीजन/वायु में दहन होिा है ।
(II) एर्थेनॉि को 443 K पर आस्िक्ट्य सांि H2SO4 के सार्थ गमा स्कया जािा
है ।
(III) एर्थेनॉि अम्िीकृ ि पोटैस्ियम डाइिोमेट के सार्थ अस्िस्िया करिा है । 5

35. (क) (i) मानव मादा जनन िंत्र के स्नम्नस्िस्खि िागों के काया स्िस्खए :
(I) अण्डािय
(II) अडं वास्हका (फे िोस्पयन ट्यबू )
(III) गिाािय

(ii) परुु र्ों (मानव नरों) द्वारा उपयोग की जाने वािी दो गिास्नरोिक स्वस्ियों का संक्षेप में
उल्िेख कीस्जए । 5

अथवा
(ख) (i) तवपरागण और परपरागण के बीच स्विेदन कीस्जए ।
(ii) नीचे स्दए गए आरे ख में A, B और C की पहचान कीस्जए और प्रत्येक िाग का एक
काया स्िस्खए । 5

A

B

C

*31/1/1* 20 #

*ECNEICS*
(ii) Write chemical equation to show what happens when
ethanol :
(I) burns in oxygen/air.
(II) is heated at 443 K in excess conc. H2SO4.

(III) reacts with acidified potassium dichromate. 5

35. (a) (i) Write the functions of the following parts of human female
reproductive system :
(I) Ovary
(II) Fallopian tube
(III) Uterus

(ii) State briefly two contraceptive methods used by human
males. 5

OR

(b) (i) Differentiate between self-pollination and cross-pollination.

(ii) Identify A, B and C in the diagram given below and write
one function of each. 5

A

B

C

*31/1/1* 21 # [ P.T.O. ]

*ECNEICS*
36. (क) (i) स्कसी िेंस ‘X’ की क्षमिा – 2·5 D है । इस िेंस का नाम स्िस्खए और इसकी
फोकस दरू ी cm में स्निााररि कीस्जए । नेत्र स्चस्कत्सक स्कस दृस्ि दोर् के संिोिन के
स्िए इस प्रकार के िेंस को संिोिक िेंस के रूप में स्निााररि करिे हैं ?

(ii) “स्कसी िेंस के स्िए आविान ‘m’ का मान – 2 है ।” नई कािीय स्चह्न पररपाटी का
उपयोग करिे हुए और यह मानिे हुए स्क कोई स्बम्ब इस िेंस के प्रकास्िक के न्ि से
20 cm की दरू ी पर है, स्नम्नस्िस्खि का उल्िेख कीस्जए :

(I) बनने वािे प्रस्िस्बम्ब की प्रकृ स्ि;
(II) ु ना में प्रस्िस्बम्ब का साइज़;
स्बम्ब के साइज़ की िि
(III) प्रस्िस्बम्ब की स्तर्थस्ि, िर्था

(IV) प्रस्िस्बम्ब की ऊाँ चाई का स्चह्न ।

(iii) दो िेंसों A और B की फोकस दरू ी के संख्यात्मक मान िमि: 10 cm और
20 cm हैं । इन दोनों में से कौन-सा िेंस अस्िसाररिा/अपसाररिा की उच्चिर कोस्ट
दिााएगा ? अपने उत्तर की कारण सस्हि पस्ु ि कीस्जए । 5

अथवा

(ख) (i) स्कसी कााँच के आयिाकार तिैब से प्रकाि की स्कसी स्करण का अपवस्िाि होना
दिााने के स्िए स्करण आरे ख खींस्चए जबस्क प्रकाि स्करण वायु से कााँच में स्ियाकि:
आपिन कर रही है ।

(ii) प्रकाि के अपविान का तनेि का स्नयम स्िस्खए ।

(iii) (I) स्बम्ब दरू ी िर्था (II) आविान के आिार पर स्कसी उत्ति िेंस और स्कसी
अविि िेंस द्वारा बने आिासी प्रस्िस्बम्बों के बीच स्विेदन कीस्जए । 5

*31/1/1* 22 #

*ECNEICS*
36. (a) (i) The power of a lens ‘X’ is – 2·5 D. Name the lens and
determine its focal length in cm. For which eye defect of
vision will an optician prescribe this type of lens as a
corrective lens ?

(ii) ‘‘The value of magnification ‘m’ for a lens is – 2.’’ Using new
Cartesian Sign Convention and considering that an object is
placed at a distance of 20 cm from the optical centre of this
lens, state :

(I) the nature of the image formed;

(II) size of the image compared to the size of the object;

(III) position of the image, and

(IV) sign of the height of the image.

(iii) The numerical values of the focal lengths of two lenses A
and B are 10 cm and 20 cm respectively. Which one of the
two will show higher degree of convergence/divergence ?
Give reason to justify your answer. 5

OR

(b) (i) Draw a ray diagram to show the refraction of a ray of light
through a rectangular glass slab when it falls obliquely from
air into glass.

(ii) State Snell’s law of refraction of light.

(iii) Differentiate between the virtual images formed by a convex
lens and a concave lens on the basis of :
(I) object distance, and
(II) magnification. 5

*31/1/1* 23 # [ P.T.O. ]

*ECNEICS*
खण्ड ङ >
निम्िन न त प्रश्ि स्रोत-आर्धरित/के स-आर्धरित प्रश्ि हैं । के स को सधवर्धिीपवू ाक पऩिए औि नर्दए गए प्रश्िों के उत्ति
र्दीनिए ।
37. समिु ी जि में कई प्रकार के िवण घि ु े होिे हैं । सािारण नमक को इन िवणों से पृर्थक स्कया जािा
है । स्वश्व के कई िागों में िी ठोस िवण का स्नक्षेप होिा है । ब़िे आकार के यह स्कतटि प्राय:
अपिव्यों (अिस्ु ियों) के कारण िरू े रंग के होिे हैं । इसे खस्नज नमक कहिे हैं । इसका खनन िी कोयिे
की िााँस्ि होिा है । सािारण नमक दैस्नक जीवन में उपयोग होने वािे रसायनों के स्िए एक महत्त्वपणू ा
कच्ची सामग्री है ।
(क) िवण-जि (ब्राइन) के स्वद्यिु -अपघटन से उत्पन्न उत्पादों को दिााने के स्िए सिं स्ु िि
रासायस्नक समीकरण स्िस्खए । 1

(ख) िवण-जि (ब्राइन) के स्वद्यिु -अपघटन से प्राप्त स्कसी िी एक उत्पाद के दो उपयोगों की सचू ी
बनाइए । 1

(ग) (i) स्कसी दबु ाि असंक्षारक क्षारीय िवण ‘A’ का उपयोग खाने को िीघ्रिा से पकाने में
स्कया जािा है । इसे गमा करने पर कोई यौस्गक ‘B’ बनिा है स्जसका उपयोग जि की
तर्थायी कठोरिा को दरू करने में स्कया जािा है । A और B को पहचास्नए िर्था A को
गमा करने पर होने वािी अस्िस्िया का समीकरण िी स्िस्खए । 2
अथवा
(ग) (ii) स्ितटिन के जि की पररिार्ा स्िस्खए । उन दो िवणों का उदाहरण दीस्जए स्जनमें
स्ितटिन का जि होिा है । 2

38. सिी जीवों का अनरु क्षण काया स्नरन्िर होना चास्हए । यह उस समय िी चििे रहना चास्हए जब वे कोई
स्विेर् काया नहीं कर रहे होिे हैं । जब हम सो रहे हों अर्थवा अपनी कक्षा में बैठे होिे हैं, उस समय िी
यह अनरु क्षण का काया चििा रहना चास्हए । कोस्िकाओ ं और ऊिकों की क्षस्ि और टूट-फूट को
रोकने िर्था अनरु क्षण प्रस्ियाओ ं के स्िए ऊजाा की आवश्यकिा होिी है । यह ऊजाा एकि जीव के
िरीर को तवपोस्र्यों, स्जन्हें उत्पादक कहिे हैं, से प्राप्त होिी है ।
(क) उस प्रस्िया का नाम और पररिार्ा स्िस्खए स्जसके द्वारा हरे पादप िोजन स्नस्माि करिे हैं । 1

(ख) उपयाि
ु प्रस्िया में होने वािी अस्िस्िया का रासायस्नक समीकरण स्िस्खए । 1

*31/1/1* 24 #

*ECNEICS*
SECTION E

The following questions are Source-based/Case-based questions. Read the case
carefully and answer the questions that follow.

37. Seawater contains many salts dissolved in it. Common salt is separated
from these salts. Deposits of solid salt are also found in several parts of
the world. These large crystals are often brown due to impurities. This is
called rock salt and is mined like coal. The common salt is an important
raw material for chemicals of daily use.

(a) Write balanced chemical equations to show the products formed
during electrolysis of brine. 1

(b) List two uses of any one product obtained during electrolysis of
brine. 1

(c) (i) A mild non-corrosive basic salt ‘A’, used for faster cooking, is
strongly heated to produce a compound ‘B’, that is used for
removing permanent hardness of water. Identify A and B
and also write the equation for the reaction that occurs when
A is heated. 2

OR

(c) (ii) Define water of crystallisation. Give two examples of salts
that have water of crystallisation. 2

38. The maintenance functions of all living organisms must go on even when
they are not doing anything particular. Even when we are just sitting in
a class or even asleep, this maintenance job has to go on. These
maintenance processes require energy to prevent damage and
break-down of cells and tissues, which is obtained by the individual
organism from the food prepared by the autotrophs, called producers.

(a) Name and define the process by which green plants prepare food. 1

(b) Write chemical equation involved in the above process. 1

*31/1/1* 25 # [ P.T.O. ]

*ECNEICS*
(ग) (i) मरुद् स्िद (मरुतर्थिी) पौिों द्वारा िोजन के संश्िेर्ण के समय होने वािी घटनाओ ं का
उस्चि अनि ु म में उल्िेख कीस्जए । 2

अथवा
(ग) (ii) कारण सस्हि व्याख्या कीस्जए स्क (I) घटा वािे (मेघाच्छन्न) मौसम में, िर्था
(II) ििू द्वारा रंध्रों को बदं कर स्दए जाने पर हरे पादपों द्वारा िोजन स्नमााण करने की
दर पर क्ट्या प्रिाव प़ििा है । 2

39. हम अपने घरों में स्वद्यिु िस्क्ट्ि की आपस्ू िा मख्ु य िारों, स्जसे मेन्स िी कहिे हैं, से प्राप्त करिे हैं । ये
मख्ु य िार या िो िरिी पर िगे स्वद्यिु खम्बों के सहारे अर्थवा िस्ू मगि के बिों द्वारा हमारे घरों िक
पहुचाँ िे हैं । हमारे देि में इस आपस्ू िा के दो िारों (स्वद्यन्ु मय िार िर्था उदासीन िार) के बीच 220 V का
स्विवान्िर होिा है ।
(क) हमारे घरों को आने वािी आपस्ू िा स्जन िाइन िारों द्वारा होिी है उनके स्वद्यिु रोिी आवरणों के
रंग स्िस्खए । 1

(ख) 220 V के स्कसी स्वद्यि
ु पररपर्थ का िारा अनमु िाक
ं क्ट्या होना चास्हए स्क उस पररपर्थ पर
1 kW िस्क्ट्ि अनम
ु िांक की स्वद्यिु इतिरी का प्रचािन स्कया जा सके ? 1

(ग) (i) िसू म्पका िार का क्ट्या काया है ? स्वद्यिु इतिरी जैसे घरे िू स्वद्यिु सास्ित्रों में िसू म्पका
िार के महत्त्व का उल्िेख कीस्जए । 2

अथवा
(ग) (ii) स्वद्यिु से होने वािी दघु ाटनाओ ं से बचाव के स्िए िी जाने वािी दो साविास्नयों की
सचू ी बनाइए । उल्िेख कीस्जए स्क ये साविास्नयााँ स्कस प्रकार पररपर्थ/सास्ित्र को
संिास्वि क्षस्ि से बचािी हैं । 2

*31/1/1* 26 #

*ECNEICS*
(c) (i) State in proper sequence the events that occur in synthesis
of food by desert plants. 2

OR

(c) (ii) Explain giving reasons what happens to the rate at which
the green plants will prepare food 2
(I) during cloudy weather, and
(II) when stomata get blocked due to dust.

39. In our homes, we receive the supply of electric power through a main
supply also called mains, either supported through overhead electric
poles or by underground cables. In our country the potential difference
between the two wires (live wire and neutral wire) of this supply is 220 V.

(a) Write the colours of the insulation covers of the line wires through
which supply comes to our homes. 1

(b) What should be the current rating of the electric circuit (220 V) so
that an electric iron of 1 kW power rating can be operated ? 1

(c) (i) What is the function of the earth wire ? State the advantage
of the earth wire in domestic electric appliances such as
electric iron. 2

OR

(c) (ii) List two precautions to be taken to avoid electrical accidents.
State how these precautions prevent possible damage to the
circuit/appliance. 2

*31/1/1* 27 # [ P.T.O. ]

Marking Scheme
Strictly Confidential
(For Internal and Restricted use only)
Secondary School Examination, 2025
SUBJECT NAME : SCIENCE (Q.P. CODE 31/1/1)

General Instructions: -
You are aware that evaluation is the most important process in the actual and correct
assessment of the candidates. A small mistake in evaluation may lead to serious problems
1 which may affect the future of the candidates, education system and teaching profession.
To avoid mistakes, it is requested that before starting evaluation, you must read and
understand the spot evaluation guidelines carefully.
“Evaluation policy is a confidential policy as it is related to the confidentiality of the
examinations conducted, Evaluation done and several other aspects. Its leakage to
2 public in any manner could lead to derailment of the examination system and affect
the life and future of millions of candidates. Sharing this policy/document to anyone,
publishing in any magazine and printing in Newspaper/Website, etc. may invite action
under various rules of the Board and IPC.”
Evaluation is to be done as per instructions provided in the Marking Scheme. It should not
be done according to one’s own interpretation or any other consideration. Marking Scheme
3 should be strictly adhered to and religiously followed. However, while evaluating,
answers which are based on latest information or knowledge and/or are innovative,
they may be assessed for their correctness otherwise and due marks be awarded to
them. In class-X, while evaluating two competency-based questions, please try to
understand given answer and even if reply is not from marking scheme but correct
competency is enumerated by the candidate, due marks should be awarded
The Marking Scheme carries only suggested value points for the answers.

4 These are in the nature of Guidelines only and do not constitute the complete answer. The
students can have their own expression and if the expression is correct, the due marks
should be awarded accordingly.
5 The Head-Examiner must go through the first five answer books evaluated by each
evaluator on the first day, to ensure that evaluation has been carried out as per the
instructions given in the Marking Scheme. If there is any variation, the same should be
zero after deliberation and discussion. The remaining answer books meant for evaluation
shall be given only after ensuring that there is no significant variation in the marking of
individual evaluators.
6 Evaluators will mark( √ ) wherever answer is correct. For wrong answer CROSS ‘X’ be
marked. Evaluators will not put right (✓)while evaluating which gives an impression that
answer is correct and no marks are awarded. This is most common mistake which
evaluators are committing.
7 If a question has parts, please award marks on the right-hand side for each part. Marks
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled. This may be followed strictly.
8 If a question does not have any parts, marks must be awarded in the left-hand margin and
encircled. This may also be followed strictly.
9 If a student has attempted an extra question, answer of the question deserving more marks
should be retained and the other answer scored out with a note “Extra Question”.
10 No marks to be deducted for the cumulative effect of an error. It should be penalized only
once.
11 A full scale of marks 80 (example 0 to 80/70/60/50/40/30 marks as given in Question
Paper) has to be used. Please do not hesitate to award full marks if the answer deserves it.
12 Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours
every day and evaluate 20 answer books per day in main subjects and 25 answer books per

Page 1 of 12 X_086_ 31/1/1

day in other subjects (Details are given in Spot Guidelines).This is in view of the reduced
syllabus and number of questions in question paper.
13 • Ensure that you do not make the following common types of errors committed by
the Examiner in the past:-
• Leaving answer or part thereof unassessed in an answer book.
• Giving more marks for an answer than assigned to it.
• Wrong totaling of marks awarded on an answer.
• Wrong transfer of marks from the inside pages of the answer book to the title page.
• Wrong question wise totaling on the title page.
• Wrong totaling of marks of the two columns on the title page.
• Wrong grand total.
• Marks in words and figures not tallying/not same.
• Wrong transfer of marks from the answer book to online award list.
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark
is correctly and clearly indicated. It should merely be a line. Same is with the X for
incorrect answer.)
• Half or a part of answer marked correct and the rest as wrong, but no marks
awarded.
14 While evaluating the answer books if the answer is found to be totally incorrect, it should
be marked as cross (X) and awarded zero (0)Marks.
15 Any unassessed portion, non-carrying over of marks to the title page, or totaling error
detected by the candidate shall damage the prestige of all the personnel engaged in the
evaluation work as also of the Board. Hence, in order to uphold the prestige of all
concerned, it is again reiterated that the instructions be followed meticulously and
judiciously.
16 The Examiners should acquaint themselves with the guidelines given in the “Guidelines
for Spot Evaluation” before starting the actual evaluation.
17 Every Examiner shall also ensure that all the answers are evaluated, marks carried over to
the title page, correctly totaled and written in figures and words.
18. The candidates are entitled to obtain photocopy of the Answer Book on request on
payment of the prescribed processing fee. All Examiners/Additional Head Examiners/Head
Examiners are once again reminded that they must ensure that evaluation is carried out
strictly as per value points for each answer as given in the Marking Scheme.

Page 2 of 12 X_086_ 31/1/1

SECONDARY SCHOOL EXAMINATION, 2025
MARKING SCHEME
CLASS: X SCIENCE (Subject Code–086)
[ Paper Code: 31/1/1]
Maximum Marks: 80

Q. EXPECTED ANSWERS / VALUE POINTS Marks Total
No. Marks
SECTION A
1. D /1: 8 1 1
2. B / Al2O3 and MgO 1 1
3. D / Weak acid, neutral, strong base, strong acid 1 1
4. A / Salt and water is formed 1 1
5. C / It has weak electrostatic forces of attraction between its 1 1
oppositely charged ions.
6. B / Calcium and Magnesium 1 1
7. A/ 1 1

8. C / starch into simple sugars 1 1
9. D / Auxins 1 1
10. C / (i) and (iii) 1 1
11. C / 100% round and yellow 1 1
12. D / Cytoplasm and Oxygen deficient muscle cells 1 1
13. A / (i) and (ii) 1 1
14. B / Presbyopia and bifocal lens 1 1
15. D / (ii) and (iv) 1 1
16. D / 99% 1 1
17. B / Both Assertion (A) and Reason (R) are true, but Reason (R) is 1 1
not the correct explanation of Assertion (A).
18. C / Assertion (A) is true, but Reason (R) is false. 1 1
19. A / Both Assertion (A) and Reason (R) are true and Reason (R) is 1 1
the correct explanation of Assertion (A).
20. B / Both Assertion (A) and Reason (R) are true, but Reason (R) is 1 1
not the correct explanation of Assertion (A).
SECTION B
21. • Evolution of gas 1
• Change / Rise in temperature 1 2
22.

diagram 1
labelling 1 2

Page 3 of 12 X_086_ 31/1/1

23. (a)
• Plugging of the leak in blood vessels prevents lowering of
the blood pressure / maintains the efficiency of the pumping 1
system.

• Platelets ½
• Help to clot the blood at the site of injury. ½
OR
(b)
(i) Plants have low energy needs because they have a large
1
proportion of dead cells in many tissues / Plants have
low energy needs as they do not move

(ii) Translocation of soluble products of photosynthesis from
1
leaves to other parts of the plant / It transports amino
acids and other substances to storage organs of roots, 2
fruits and seeds and to growing organs.
24 u = - 60 cm f = -30 cm

1 1 1 ½
= –
𝑓 𝑣 𝑢

1 1 1
= – ½
– 30 𝑐𝑚 𝑣 – 60 𝑐𝑚

1 1 1
= –
𝑣 −30 60

−3 1
 v = – 20 cm
= 1
60 𝑐𝑚 𝑣
Position of image is 20 cm from a concave lens. 2

25. (a)
𝑅 ½
Resistance of each part =
3

1 1 1 1
= + + ½
𝑅𝑝 𝑅1 𝑅2 𝑅3
1 1 1 1
= + + ½
𝑅𝑝 𝑅/3 𝑅/3 R/3

1 3 3 3 9
= + + =
𝑅𝑝 𝑅 𝑅 𝑅 𝑅

𝑅 ½
 Rp =
9

OR
(b)
• Electric power is the rate at which electrical energy is 1

Page 4 of 12 X_086_ 31/1/1

consumed or dissipated in an electrical circuit. / Electric
power is electrical energy consumed per unit time.
• When 1A current at 1V potential difference flows in a circuit.
1
/ Power consumed is 1W when 1J electrical energy is 2
consumed in 1 s.
26. Chemicals/pesticides used by farmers get washed down into the
soil or water bodies and affect biotic and abiotic components of the
ecosystem. These chemicals are mostly non-biodegradable and get
accumulated progressively at each trophic level (Biological
magnification). Thus, the health of the organisms of all trophic 2
levels is affected. 2
SECTION C
27. (a)
3 𝑀𝑛𝑂2 (𝑠) + 4 𝐴𝑙(𝑠) → 3 𝑀𝑛(𝑙) + 2 𝐴𝑙2 𝑂3 (𝑠) + ℎ𝑒𝑎𝑡
1
𝐹𝑒2 𝑂3 (𝑠) + 2 𝐴𝑙(𝑠) → 2 𝐹𝑒(𝑙) + 𝐴𝑙2 𝑂3 (𝑠) + ℎ𝑒𝑎𝑡 1

(Award marks if explained through statement or any other
reactions.)
(b)
Metals towards the top of the reactivity series (Na, Mg, Ca) have 1 3
more affinity for oxygen than carbon.
28. (a)
➢ Take three test tubes and place clean iron nails in each of
them.
➢ Label these test tubes A, B and C.
➢ Pour some water in test tube A and cork it.
➢ Pour boiled distilled water in test tube B, add about 1 mL of
oil and cork it. The oil will float on water and prevent the air
from dissolving in the water.
➢ Put some anhydrous calcium chloride in test tube C and cork
it. Anhydrous calcium chloride will absorb the moisture, if
any, from the air.
Iron nails rust in test tube A, but they do not rust in test tubes B
and C.
Rusting of iron takes place when exposed to both air and water.
/ 3

Page 5 of 12 X_086_ 31/1/1

Iron nails rust in test tube A, but they do not rust in test tubes B
and C.
Rusting of iron takes place when exposed to both air and water.

(Note: if a student explains activity through description or through
labelled diagram, award full marks.)

OR

(b) (i)
• Sodium, Potassium, Lithium ½,½
(any two)
• Observations:
➢ A violent reaction occurs.
➢ Large amount of heat is evolved. 1½
➢ Evolved gas may catch fire.

(ii) The gas (bubbles) burns with a pop sound ½
3
29. (a) Plant cells use electrical– chemical means to convey 1
information. /The information that touch has occurred must be
communicated

(b) Plant cells change shape by changing the amount of water in 1
them (swelling or shrinking).

(c)

Movement in touch-me-not Movement of tendrils in pea
Plant plant
It is growth independent It is growth dependent
It does not take place in the It takes place in the direction
direction of stimulus of stimulus
It is also called as nastic It is also called as tropic
movement. movement 1
(any other) 3
(Any one difference)
30. (a)
Chromosomes carry genes which control the traits of an
organism/chromosomes contain information for inheritance of 1
features from parents to next generation in the form of DNA(Deoxy
ribonucleic acid) molecule.
(b)
• Each cell has two copies of each chromosome, one from
male and the other from female parents which get halved 1
during the formation of germ cells/gametes.
• After fusion of the germ cells zygote is formed which
restores the normal number of chromosomes and the same 1
amount of DNA in the progeny. 3

Page 6 of 12 X_086_ 31/1/1

31. (i)

IMAGE

1½

OBJECT

(ii)
IMAGE

A 1½

B

OBJECT

(Note: Deduct ½ mark if arrows are not drawn.)
3
32. (a)
1 1 1 1
= + =  R1 = 6 
𝑅1 10 𝛺 15 𝛺 6𝛺

1 1 1 100
= + =  R2 = 24 
𝑅2 60 𝛺 40 𝛺 2400 𝛺

∵ R1 and R2 are in series

1
 Rtotal = R1 + R2 = (6 + 24) = 30 

𝑉 15 𝑉
(b) V = IR  I= = = 0·5 A 1
𝑅 30 𝛺

(c) V = IR1 = 0·5 A  6  = 3·0 V 1
3
33. (a)
𝑙
• R=𝜌 1
𝐴

𝑅𝐴
= ½
𝑙
𝑜ℎ𝑚 × (𝑚𝑒𝑡𝑟𝑒)2
• SI unit of  =
𝑚𝑒𝑡𝑟𝑒 ½
= ohm meter

Page 7 of 12 X_086_ 31/1/1

(b) Resistivity of alloy is higher than pure metals. / They do not
oxidise (burn) readily at high temperatures. 1 3

SECTION D
34. (a)

(i)

½, ½
(any two)

(ii) (I) Chloropropane ½
(II) Butanone/ Butan-2-one ½

(iii) (I)

1

(II)

CH3CH=CH2 + H2 CH3CH2CH3 1

𝐴𝑐𝑖𝑑
(III) 𝐶𝐻3 𝐶𝑂𝑂𝐻 + 𝐶2 𝐻5 𝑂𝐻 → 𝐶𝐻3 𝐶𝑂𝑂𝐶2 𝐻5 + 𝐻2 𝑂 1

OR

(b)
(i) X = Ethanol/ Ethyl alcohol/ C2H5OH ½
Y = Sodium ethoxide/ C2H5ONa ½
Z = Hydrogen/H2 ½

1 ½
𝐶𝐻3 𝐶𝐻2 𝑂𝐻 + 𝑁𝑎 → 𝐶𝐻3 𝐶𝐻2 𝑂𝑁𝑎 + 𝐻2
2
X Y Z
(ii)
(I) 1

(II)
1

Page 8 of 12 X_086_ 31/1/1

(III)

1

(No mark to be deducted if equations are not balanced.) 5

35. (a) (i)
(I) Ovary: Produces female gamete (egg) and female ½,½
hormones(oestrogen).
(II) Fallopian tube: Site of Fertilization 1

(III) Uterus: Site of Implantation and embryonic development. 1

(ii) Methods of contraception used by males:
• Mechanical barrier - Condoms 1
• Surgical method – blocking the vas deferens in males 1
(Vasectomy)

OR
(b) (i)
Self-pollination Cross-pollination
Pollen grains are transferred Transfer of pollen grains from
from stamen to the stigma of the stamen of one flower to the 1+1
same flower. stigma of another flower of
same species.

(ii)
A – Stigma: Receives pollen and provides suitable environment 1
for its germination.
B –Pollen tube: Carries males germ cells (gametes) to the female 1
gamete situated in the ovary.
C – Egg Cell (Female germ cell): Fuses with male gamete and forms 1
zygote. 5
36. (a) (i)
• Concave lens ½
1
• P= ½
𝑓(𝑚)
1
– 25 =
𝑓
10 ½
f= = – 0·4 m = – 40 cm
– 2⋅5
• Myopia ½

(ii) (I) Real and inverted
(II) magnified image /size of image is
double the size of object
(III) beyond 2F/ on the other side as that of object ½×4
(IV) Negative
(iii)
• The lens with focal length 10 cm ½
• less focal length, more converging/diverging power ½

Page 9 of 12 X_086_ 31/1/1

OR
(b) (i)

2

( if arrows not marked , deduct half mark)

(ii) The ratio of sine of angle of incidence to the sine of angle of
1
refraction is a constant, for the light of a given colour and for a
given pair of media. /
1
(iii)

Convex Lens Concave Lens
(I) Object to be placed between Object can be placed 1
O and F anywhere in front of the lens
(II) Magnified image Diminished image
5
SECTION E
37. 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦
(a) 2 𝑁𝑎𝐶𝑙 + 2 𝐻2 𝑂 → 2 𝑁𝑎𝑂𝐻 + 𝐻2 + 𝐶𝑙2
1
(b)
Uses of NaOH : Degreasing metals/ Soaps and Detergents/ paper
making/ artificial fibres/ preparation of bleach ½,½
Uses of H2: As fuel/ Margarine/ In preparation of ammonia for
fertilizers/Preparation of HCl
Uses of Cl2 : Disinfectant/ PVC/ water treatment/ in swimming
pools/ CFC’s/ preparation of bleach/ preparation of HCl/ pesticides
(Any two uses of anyone product)
(c) (i) A – NaHCO3/ Sodium Hydrogen Carbonate/ Baking ½
soda
B – Na2CO3 / Sodium Carbonate ½
ℎ𝑒𝑎𝑡
2 𝑁𝑎𝐻𝐶𝑂3 → 𝑁𝑎2 𝐶𝑂3 + 𝐻2 𝑂 + 𝐶𝑂2 1
A B
OR
(c) (ii) • The fixed number of water molecules present in
one formula unit of a salt. 1
• CuSO4.5H2O/Copper Sulphate pentahydrate/Blue vitrol
• CaSO4.2H2O/Gypsum/Calcium sulphate dihydrate
• Na2CO3.10H2O/Washing Soda/Sodium carbonate
decahydrate

Page 10 of 12 X_086_ 31/1/1

• FeSO4.7H2O/ Green Vitrol/Ferrous sulphate hepta hydrate
• CaSO4 . ½ H2O/ Calcium Sulphate hemihydrate /POP
(Any two examples ) ½,½
4
38. (a)
Photosynthesis ½
A process by which green plants capture sunlight and convert it to
chemical energy with the help of chlorophyll / Process by which ½
carbon dioxide and water is converted into carbohydrates in the
presence of sunlight chlorophyll and water.

(b)
1

(c) (i)

• Absorption of light energy by chlorophyll
• Conversion of light energy to chemical energy.
• Reduction of carbon dioxide to carbohydrates.
• Desert plants take up CO2 at night and prepare 2
intermediate, which is acted upon by the energy absorbed by the
chlorophyll during the day.
OR
(c) (ii) (I) Decrease the rate of photosynthesis due to low amount of 1
sunlight.
(II) Decreases the rate of photosynthesis due to reduced 1
gaseous exchange. 4
39. (a) Live wire- Red ½
Neutral wire- Black ½

(b) Power, P = 1 kW = 1  1000 W = 1000 W
Voltage, V = 220 V
Current drawn I =? P=VI ½
1000 𝑊
I= = 4·54 A
220 𝑉
Current rating should be of 5A. ½
(c) (i)
• The earth wire provides a low resistance conducting path for
the current which ensures that any leakage of current to flow 1
to the metallic body of the appliances, keeps its potential to
that of the earth.
• The user will not get an electric shock. 1
OR
(c) (ii) ½
• Fuse wire ½
• Earth wire
• A fuse in a circuit prevents damage to the circuit due to ½
overloading.
• Earth wire prevents electric shock due to leakage of current. ½ 4

Page 11 of 12 X_086_ 31/1/1

Page 12 of 12 X_086_ 31/1/1

Marking Scheme
Strictly Confidential
(For Internal and Restricted use only)
Secondary School Examination, 2025
SUBJECT NAME : SCIENCE (Q.P. CODE 31/1/2)

General Instructions: -
You are aware that evaluation is the most important process in the actual and correct
assessment of the candidates. A small mistake in evaluation may lead to serious problems
1 which may affect the future of the candidates, education system and teaching profession.
To avoid mistakes, it is requested that before starting evaluation, you must read and
understand the spot evaluation guidelines carefully.
“Evaluation policy is a confidential policy as it is related to the confidentiality of the
examinations conducted, Evaluation done and several other aspects. Its leakage to
2 public in any manner could lead to derailment of the examination system and affect
the life and future of millions of candidates. Sharing this policy/document to anyone,
publishing in any magazine and printing in Newspaper/Website, etc. may invite action
under various rules of the Board and IPC.”
Evaluation is to be done as per instructions provided in the Marking Scheme. It should not
be done according to one’s own interpretation or any other consideration. Marking Scheme
3 should be strictly adhered to and religiously followed. However, while evaluating,
answers which are based on latest information or knowledge and/or are innovative,
they may be assessed for their correctness otherwise and due marks be awarded to
them. In class-X, while evaluating two competency-based questions, please try to
understand given answer and even if reply is not from marking scheme but correct
competency is enumerated by the candidate, due marks should be awarded
The Marking Scheme carries only suggested value points for the answers.

4 These are in the nature of Guidelines only and do not constitute the complete answer. The
students can have their own expression and if the expression is correct, the due marks
should be awarded accordingly.
5 The Head-Examiner must go through the first five answer books evaluated by each
evaluator on the first day, to ensure that evaluation has been carried out as per the
instructions given in the Marking Scheme. If there is any variation, the same should be
zero after deliberation and discussion. The remaining answer books meant for evaluation
shall be given only after ensuring that there is no significant variation in the marking of
individual evaluators.
6 Evaluators will mark( √ ) wherever answer is correct. For wrong answer CROSS ‘X’ be
marked. Evaluators will not put right (✓)while evaluating which gives an impression that
answer is correct and no marks are awarded. This is most common mistake which
evaluators are committing.
7 If a question has parts, please award marks on the right-hand side for each part. Marks
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled. This may be followed strictly.
8 If a question does not have any parts, marks must be awarded in the left-hand margin and
encircled. This may also be followed strictly.
9 If a student has attempted an extra question, answer of the question deserving more marks
should be retained and the other answer scored out with a note “Extra Question”.
10 No marks to be deducted for the cumulative effect of an error. It should be penalized only
once.
11 A full scale of marks 80 (example 0 to 80/70/60/50/40/30 marks as given in Question
Paper) has to be used. Please do not hesitate to award full marks if the answer deserves it.
12 Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours
every day and evaluate 20 answer books per day in main subjects and 25 answer books per
day in other subjects (Details are given in Spot Guidelines).This is in view of the reduced
syllabus and number of questions in question paper.

Page 1 of 12 X_086_ 31/1/2

13 • Ensure that you do not make the following common types of errors committed by
the Examiner in the past:-
• Leaving answer or part thereof unassessed in an answer book.
• Giving more marks for an answer than assigned to it.
• Wrong totaling of marks awarded on an answer.
• Wrong transfer of marks from the inside pages of the answer book to the title page.
• Wrong question wise totaling on the title page.
• Wrong totaling of marks of the two columns on the title page.
• Wrong grand total.
• Marks in words and figures not tallying/not same.
• Wrong transfer of marks from the answer book to online award list.
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark
is correctly and clearly indicated. It should merely be a line. Same is with the X for
incorrect answer.)
• Half or a part of answer marked correct and the rest as wrong, but no marks
awarded.
14 While evaluating the answer books if the answer is found to be totally incorrect, it should
be marked as cross (X) and awarded zero (0)Marks.
15 Any unassessed portion, non-carrying over of marks to the title page, or totaling error
detected by the candidate shall damage the prestige of all the personnel engaged in the
evaluation work as also of the Board. Hence, in order to uphold the prestige of all
concerned, it is again reiterated that the instructions be followed meticulously and
judiciously.
16 The Examiners should acquaint themselves with the guidelines given in the “Guidelines
for Spot Evaluation” before starting the actual evaluation.
17 Every Examiner shall also ensure that all the answers are evaluated, marks carried over to
the title page, correctly totaled and written in figures and words.
18. The candidates are entitled to obtain photocopy of the Answer Book on request on
payment of the prescribed processing fee. All Examiners/Additional Head Examiners/Head
Examiners are once again reminded that they must ensure that evaluation is carried out
strictly as per value points for each answer as given in the Marking Scheme.

Page 2 of 12 X_086_ 31/1/2

SECONDARY SCHOOL EXAMINATION, 2025
MARKING SCHEME
CLASS: X [SCIENCE (Subject Code–086)]
[ Paper Code: 31/1/2]
Maximum Marks: 80
Q. EXPECTED ANSWERS / VALUE POINTS Marks Total
No. Marks
SECTION A
1. A/ 1 1

2. B / Calcium and Magnesium 1 1
3. C/FeSO4 1 1
4. C / It has weak electrostatic forces of attraction between its oppositely 1 1
charged ions.
5. D/1:8 1 1
6. A / Salt and water is formed 1 1
7. B / Al2O3 and MgO 1 1
8. D / Auxins 1 1
9. C / starch into simple sugars 1 1
10. C / 100% round and yellow 1 1
11. C / (i) and (iii) 1 1
12 D / Cytoplasm and Oxygen deficient muscle cells 1 1
13. D/Green light deviates more than the orange light 1 1
14. A / (i) and (ii) 1 1
15. D / 99% 1 1
16. D / (ii) and (iv) 1 1
17. C / Assertion (A) is true, but Reason (R) is false. 1 1
18. B / Both Assertion (A) and Reason (R) are true, but Reason (R) is not 1 1
the correct explanation of Assertion (A).
19. B / Both Assertion (A) and Reason (R) are true, but Reason (R) is not 1 1
the correct explanation of Assertion (A).
20. A / Both Assertion (A) and Reason (R) are true and Reason (R) is the 1 1
correct explanation of Assertion (A).

SECTION B
21. Chemicals/pesticides used by farmers get washed down into the soil or
water bodies and affect biotic and abiotic components of the
ecosystem. These chemicals are mostly non-biodegradable and get
accumulated progressively at each trophic level (Biological
magnification). Thus, the health of the organisms of all trophic levels 2
is affected. 2
22. • (a) Power dissipated will be:
½
• (I) minimum in circuit (ii) and
• (II) maximum in circuit (iii) ½
•
𝑉2
• Justification : Power dissipated =
𝑅

• Since voltage is same in three cases, the power dissipation

Page 3 of 12 X_086_ 31/1/2

• will be inversely proportional to the resistance of the 1

• circuit.
•
• (Award marks if explained through calculations)
•
• OR
• (b) Voltage V = 220V
• P=V x I ½

• Power P1 = 100 W P2 = 60 W
𝑃 100 𝑊
•  I1 = 1 = = 0·45 A ½
𝑉 220 𝑉
𝑃2 60 𝑊
•  I2 = = = 0·27 A ½
𝑉 220 𝑉

•  Total current drawn ½
I = I1 + I2 = 0·45 + 0·27 = 0·72 A 2
23. f = – 20 cm ; u = – 30 cm
1 1 1 ½
= +
𝑓 𝑣 𝑢
1 1 1
= −
𝑣 −20 −30 ½
1 1 1
= +
𝑣 −20 30
𝑣 = -60 cm
1
Position of image is 60 cm in front of the mirror.
2
24. (a)
• Plugging of the leak in blood vessels prevents lowering of the
blood pressure / maintains the efficiency of the pumping 1
system
½
• Platelets ½
• Help to clot the blood at the site of injury.
OR
(b)
(i) Plants have low energy needs because have a large 1
proportion of dead cells in many tissues / Plants have low
energy needs as they do not move
(ii)
Translocation of soluble products of photosynthesis from leaves to
other parts of the plant / It transports amino acids and other substances 1 2
to storage organs of roots, fruits and seeds and to growing organs.
25.

diagram 1

Page 4 of 12 X_086_ 31/1/2

labelling 1 2
26. ℎ𝑒𝑎𝑡 1
(a) 2 𝑃𝑏(𝑁𝑂3 )2 → 2 𝑃𝑏𝑂 + 4 𝑁𝑂2 + 𝑂2
(b) 𝐶𝐻4 + 2 𝑂2 → 𝐶𝑂2 + 2 𝐻2 𝑂 + 𝐻𝑒𝑎𝑡 + 𝑙𝑖𝑔ℎ𝑡 1 2
SECTION C
27. (a) When 1 coulomb of charge flows through any cross section of a
conductor in 1 second, then the electric current flowing through it is 1
1𝐶 1
ampere. / 1A =
1𝑠

• (b) Radius of wire = 0·01 cm = 0·01  10– 2
m

•  = 44  10– 8  m
• R = 14 
½
𝑙
• R=𝜌
𝐴
½
𝑅 ×𝐴 14 × 22 × (0⋅01 × 10– 2 )2
• l= =
𝜌 7 × 44 × 10– 8
𝟏𝟎– 𝟖
• = 1
𝟏𝟎– 𝟖
3
= 1·0 m

28. (a)
1 1 1 1
= + =  R1 = 6 
𝑅1 10 𝛺 15 𝛺 6𝛺

1 1 1 100
= + =  R2 = 24 
𝑅2 60 𝛺 40 𝛺 2400 𝛺

∵ R1 and R2 are in series

1
 Rtotal = R1 + R2 = (6 + 24) = 30 

𝑉 15 𝑉
(b) V = IR  I= = = 0·5 A 1
𝑅 30 𝛺

(c) V = IR = 0·5 A  6  = 3·0 V 1
3
29. (i)

IMAGE

1½

OBJECT

Page 5 of 12 X_086_ 31/1/2

(ii)

1½

(Note: Deduct ½ mark if arrows are not drawn.) 3
30. (a)
➢ Take three test tubes and place clean iron nails in each of them.
➢ Label these test tubes A, B and C.
➢ Pour some water in test tube A and cork it.
➢ Pour boiled distilled water in test tube B, add about 1 mL of oil
and cork it. The oil will float on water and prevent the air from
dissolving in the water.
➢ Put some anhydrous calcium chloride in test tube C and cork it.
Anhydrous calcium chloride will absorb the moisture, if any,
from the air.
Iron nails rust in test tube A, but they do not rust in test tubes B
and C.
Rusting of iron takes place when exposed to both air and water.
/
3

Iron nails rust in test tube A, but they do not rust in test tubes B
and C.
Rusting of iron takes place when exposed to both air and water.

(Note: if a student explains activity through description or
through labelled diagram, give full marks.)

OR
(b) (i)

Page 6 of 12 X_086_ 31/1/2

• Sodium, Potassium, Lithium ½,½
(any two)
• Observations:
➢ A violent reaction occurs.
➢ Large amount of heat is evolved. 1½
➢ Evolved gas catches fire.

(ii) The gas (bubbles) burns with a pop sound ½ 3

31. (a)
3 𝑀𝑛𝑂2 (𝑠) + 4 𝐴𝑙(𝑠) → 3 𝑀𝑛(𝑙) + 2 𝐴𝑙2 𝑂3 (𝑠) + ℎ𝑒𝑎𝑡 1

𝐹𝑒2 𝑂3 (𝑠) + 2 𝐴𝑙(𝑠) → 2 𝐹𝑒(𝑙) + 𝐴𝑙2 𝑂3 (𝑠) + ℎ𝑒𝑎𝑡 1
(Award marks if explained through statement or any other
reaction)
(b) 3
Metals towards the top of the reactivity series (Na, Mg, Ca) have more 1
affinity for oxygen than carbon.
32.
• Calculation of ratio of Seeds as per data given.
𝟖𝟎𝟎
• Round and yellow – = 9,
𝟗𝟎
𝟐𝟕𝟓
• Round and green – =3
𝟗𝟎
𝟐𝟔𝟖 1
• Wrinkled and yellow – =3
𝟗𝟎
90
Wrinkled and green – =1
90

• • Parents –
• Round and Yellow Wrinkled and Green
• RRYY  rryy
Gametes

1

(Award marks if explained through Mendel’s cross using two
separate characters)

• Appearance of new combinations of characteristics show that
traits for Round/Wrinkled and Yellow/Green seeds are 1
independently inherited/ Independent inheritance of two separate 3
traits.

Page 7 of 12 X_086_ 31/1/2

33. • (a) Gland that secretes
½
• (i) Adrenal gland
• (ii) Thyroid gland ½

• (b) If the sugar level in blood rises it is detected by cells of
pancreas which responds to produce more insulin to lower
blood sugar level.
• As the blood sugar level falls it is detected by cells of 2 3
pancreas and insulin secretion is reduced.
• SECTION D
34.
(a) (i)
• Concave lens ½
1
• P= ½
𝑓(𝑚)
1
– 25 =
𝑓
10 ½
f= = – 0·4 m = – 40 cm
– 2⋅5
• Myopia ½

(ii) (I) Real and inverted
(II) magnified image /size of image is
double the size of object ½×4
(III) beyond 2F/ on the other side as that of object
(IV) Negative
(iii)
• The lens with focal length 10 cm ½
• less focal length, more converging/diverging power ½

OR
(b) (i)

2

(if arrows not marked, deduct half mark)

(ii) The ratio of sine of angle of incidence to the sine of angle of
refraction is a constant, for the light of a given colour and for a given
pair of media. 1
/

Page 8 of 12 X_086_ 31/1/2

Convex Lens Concave Lens
(I) Object to be placed between Object can be placed anywhere 1
O and F in front of the lens 5
(II) Magnified image Diminished/smaller image 1

35. • (a) (i) A = Ethanol /Ethyl alcohol / C2H5OH ½
½
B = Ethanoic acid /Acetic acid / CH3 COOH
½
C = Ethene / C2H4/CH2=CH2
•
(ii) Molecular mass of ethene (C2H4)
1
12  2 + 1  4 = 24 + 4 = 28 u
• (iii) Brisk effervescence is observed. ½
𝐶𝐻3 𝐶𝑂𝑂𝐻 + 𝑁𝑎2 𝐶𝑂3 → 𝐶𝐻3 𝐶𝑂𝑂𝑁𝑎 + 𝐻2 𝑂 + 𝐶𝑂2 1

(iv) (Ethanoic acid)

1

OR
(b) (i)
• • Homologous series: A series of organic compounds in
which the same functional groups or hetero-atom substitutes
for hydrogen in a carbon chain/A sequence of a carbon
compound with same general formula and similar chemical 1
properties.
1
• HCOOH, CH3COOH, C2H5COOH
1
• Methanoic acid, Ethanoic acid, Propanoic acid
(any other 3 successive members)
• (ii) (I) Benzene ½
(II) Cyclohexane ½

Page 9 of 12 X_086_ 31/1/2

Benzene

OR

1

5
Cyclohexane (any other example )
36. a) (i)
(I) Ovary: Produces female gamete (egg) and female ½,½
hormones(oestrogen).
(II) Fallopian tube: Site of Fertilization 1

(III) Uterus: Site of Implantation and embryonic development. 1

(ii) Methods of contraception used by males:
• Mechanical barrier - Condoms 1
• Surgical method – blocking the vas deferens in males 1
(Vasectomy)
OR
(b) (i)
Self-pollination Cross-pollination
Pollen grains are transferred Transfer of pollen grains from
from stamen to the stigma of the stamen of one flower to the
same flower. stigma of another flower of
same species. 2

(ii)
A – Stigma: Receives pollen and provides suitable environment ½,½
for its germination.
B –Pollen tube: Carries males germ cells (gametes) to the female ½,½
gamete situated in the ovary.
C – Egg Cell: (Female germ cell): Fuses with male gamete and forms ½,½
zygote. 5
SECTION E
37. (a) Live wire- Red ½
Neutral wire- Black ½

Page 10 of 12 X_086_ 31/1/2

(b) Power, P = 1 kW = 1  1000 W = 1000 W
Voltage, V = 220 V ½
Current drawn I =? P=VI
1000 𝑊 ½
I= = 4·54 A
220 𝑉
Current rating should be of 5A.
(c) (i)
• The earth wire provides a low resistance conducting path for
the current which ensures that any leakage of current to flow to 1
the metallic body of the appliances, keeps its potential to that
of the earth.
• The user will not get an electric shock. 1
OR
(c) (ii)
• Fuse wire ½
• Earth wire ½
• A fuse in a circuit prevents damage to the circuit due to
overloading. ½
• Earth wire prevents electric shock due to leakage of current. ½ 4

38. (a)
Photosynthesis ½
A process by which green plants capture sunlight and convert it to
chemical energy with the help of chlorophyll / Process by which ½
carbon dioxide and water is converted into carbohydrates in the
presence of sunlight chlorophyll and water.

(b)

1

(c) (i)
• Absorption of light energy by chlorophyll
• Conversion of light energy to chemical energy.
• Reduction of carbon dioxide to carbohydrates.
• Desert plants take up CO2 at night and prepare an
2
intermediate, which is acted upon by the energy absorbed by
the chlorophyll during the day.

OR
(c) (ii) (I) Decrease the rate of photosynthesis due to low amount of 1
sunlight.
(II) Decreases the rate of photosynthesis due to reduced 1
gaseous exchange
4
39. 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦 1
(a) 2 𝑁𝑎𝐶𝑙 + 2 𝐻2 𝑂 → 2 𝑁𝑎𝑂𝐻 + 𝐻2 + 𝐶𝑙2

(b)
Uses of NaOH : Degreasing metals/ Soaps and Detergents/ paper
making/ artificial fibres/ preparation of bleach ½ ,½

Page 11 of 12 X_086_ 31/1/2

Uses of H2: As fuel/ Margarine/ Preparation of ammonia for ½
fertilizers/preparation of HCl
Uses of Cl2 : Disinfectant/ PVC/ water treatment/ in swimming pools/ ½
CFC’s/ preparation of bleach/ preparation of HCl/ pesticides
(Any two uses of anyone product)

(c) (i) A – NaHCO3/ Sodium Hydrogen Carbonate/Baking soda
1
B – Na2CO3 / Sodium Carbonate
ℎ𝑒𝑎𝑡
2 𝑁𝑎𝐻𝐶𝑂3 → 𝑁𝑎2 𝐶𝑂3 + 𝐻2 𝑂 + 𝐶𝑂2 1
A B
OR
(c) (ii) • The fixed number of water molecules present in
one formula unit of a salt.
• CuSO4.5H2O/ Copper Sulphate pentahydrate/Blue vitriol
• CaSO4.2H2O/Gypsum/Calcium sulphate dihydrate
• Na2CO3.10H2O/Washing Soda/Sodium carbonate decahydrate ½,½ 4
• FeSO4.7 H2O / Green Vitriol/Ferrous sulphate heptahydrate
• CaSO4. ½ H2O /Calcium Sulphate hemihydrate/POP
(Any two examples )

Page 12 of 12 X_086_ 31/1/2

Marking Scheme
Strictly Confidential
(For Internal and Restricted use only)
Secondary School Examination, 2025
SUBJECT : SCIENCE (Q.P. CODE 31/1/3)

General Instructions: -
You are aware that evaluation is the most important process in the actual and correct
assessment of the candidates. A small mistake in evaluation may lead to serious problems
1 which may affect the future of the candidates, education system and teaching profession.
To avoid mistakes, it is requested that before starting evaluation, you must read and
understand the spot evaluation guidelines carefully.
“Evaluation policy is a confidential policy as it is related to the confidentiality of the
examinations conducted, Evaluation done and several other aspects. Its leakage to
2 public in any manner could lead to derailment of the examination system and affect
the life and future of millions of candidates. Sharing this policy/document to anyone,
publishing in any magazine and printing in Newspaper/Website, etc. may invite action
under various rules of the Board and IPC.”
Evaluation is to be done as per instructions provided in the Marking Scheme. It should not
be done according to one’s own interpretation or any other consideration. Marking Scheme
3 should be strictly adhered to and religiously followed. However, while evaluating,
answers which are based on latest information or knowledge and/or are innovative,
they may be assessed for their correctness otherwise and due marks be awarded to
them. In class-X, while evaluating two competency-based questions, please try to
understand given answer and even if reply is not from marking scheme but correct
competency is enumerated by the candidate, due marks should be awarded
The Marking Scheme carries only suggested value points for the answers.

4 These are in the nature of Guidelines only and do not constitute the complete answer. The
students can have their own expression and if the expression is correct, the due marks
should be awarded accordingly.
5 The Head-Examiner must go through the first five answer books evaluated by each
evaluator on the first day, to ensure that evaluation has been carried out as per the
instructions given in the Marking Scheme. If there is any variation, the same should be
zero after deliberation and discussion. The remaining answer books meant for evaluation
shall be given only after ensuring that there is no significant variation in the marking of
individual evaluators.
6 Evaluators will mark( √ ) wherever answer is correct. For wrong answer CROSS ‘X’ be
marked. Evaluators will not put right (✓)while evaluating which gives an impression that
answer is correct and no marks are awarded. This is most common mistake which
evaluators are committing.
7 If a question has parts, please award marks on the right-hand side for each part. Marks
awarded for different parts of the question should then be totaled up and written in the left-
hand margin and encircled. This may be followed strictly.
8 If a question does not have any parts, marks must be awarded in the left-hand margin and
encircled. This may also be followed strictly.
9 If a student has attempted an extra question, answer of the question deserving more marks
should be retained and the other answer scored out with a note “Extra Question”.
10 No marks to be deducted for the cumulative effect of an error. It should be penalized only
once.
11 A full scale of marks 80 (example 0 to 80/70/60/50/40/30 marks as given in Question
Paper) has to be used. Please do not hesitate to award full marks if the answer deserves it.
12 Every examiner has to necessarily do evaluation work for full working hours i.e., 8 hours
every day and evaluate 20 answer books per day in main subjects and 25 answer books per

Page 1 of 11 X_086_31/1/3

day in other subjects (Details are given in Spot Guidelines).This is in view of the reduced
syllabus and number of questions in question paper.
13 • Ensure that you do not make the following common types of errors committed by
the Examiner in the past:-
• Leaving answer or part thereof unassessed in an answer book.
• Giving more marks for an answer than assigned to it.
• Wrong totaling of marks awarded on an answer.
• Wrong transfer of marks from the inside pages of the answer book to the title page.
• Wrong question wise totaling on the title page.
• Wrong totaling of marks of the two columns on the title page.
• Wrong grand total.
• Marks in words and figures not tallying/not same.
• Wrong transfer of marks from the answer book to online award list.
• Answers marked as correct, but marks not awarded. (Ensure that the right tick mark
is correctly and clearly indicated. It should merely be a line. Same is with the X for
incorrect answer.)
• Half or a part of answer marked correct and the rest as wrong, but no marks
awarded.
14 While evaluating the answer books if the answer is found to be totally incorrect, it should
be marked as cross (X) and awarded zero (0)Marks.
15 Any unassessed portion, non-carrying over of marks to the title page, or totaling error
detected by the candidate shall damage the prestige of all the personnel engaged in the
evaluation work as also of the Board. Hence, in order to uphold the prestige of all
concerned, it is again reiterated that the instructions be followed meticulously and
judiciously.
16 The Examiners should acquaint themselves with the guidelines given in the “Guidelines
for Spot Evaluation” before starting the actual evaluation.
17 Every Examiner shall also ensure that all the answers are evaluated, marks carried over to
the title page, correctly totaled and written in figures and words.
18. The candidates are entitled to obtain photocopy of the Answer Book on request on
payment of the prescribed processing fee. All Examiners/Additional Head Examiners/Head
Examiners are once again reminded that they must ensure that evaluation is carried out
strictly as per value points for each answer as given in the Marking Scheme.

Page 2 of 11 X_086_31/1/3

SECONDARY SCHOOL EXAMINATION, 2025
MARKING SCHEME
CLASS: X [SCIENCE (Subject Code–086)]
[ Paper Code: 31/1/3 ]
Maximum Marks: 80
Q. EXPECTED ANSWERS / VALUE POINTS Marks Total
No. Marks
SECTION A 1 1
1. B / Calcium and Magnesium 1 1
2. A/ 1 1

3. C / It has weak electrostatic forces of attraction between its oppositely 1 1
charged ions.
4. A / Salt and water is formed 1 1
5. B /5 1 1
6. B / Al2O3 and MgO 1 1
7. D/1:8 1 1
8. D / Cytoplasm and Oxygen deficient muscle cells. 1 1
9. C / 100% round and yellow 1 1
10. C / (i) and (iii) 1 1
11. D / Auxins 1 1
12. C / starch into simple sugars 1 1
13. D / 99% 1 1
14. D / (ii) and (iv) 1 1
15. A / Scattering of light 1 1
16. A / (i) and (ii) 1 1
17. B / Both Assertion (A) and Reason (R) are true, but Reason (R) is not the 1 1
correct explanation of Assertion (A).
18. A / Both Assertion (A) and Reason (R) are true and Reason (R) is the 1 1
correct explanation of Assertion (A).
19. C / Assertion (A) is true, but Reason (R) is false. 1 1
20. B / Both Assertion (A) and Reason (R) are true, but Reason (R) is not the 1 1
correct explanation of Assertion (A).
SECTION B
21. Here u = – 10 cm; f = – 15 cm ;
1 1 1
= +
𝑓 𝑣 𝑢
1 1 1 ½
= +
−15 𝑣 −10

1 1 1 ½
= +
𝑣 −15 10

v =+30 cm
1
2
Position of image is 30 cm from the mirror

22.
(a)
𝑉2 ½
P=
𝑅

Page 3 of 11 X_086_31/1/3

𝑉2
R=
𝑃
(220)2
𝑅𝐴 =
50
(220)2 ½
𝑅𝐵 =
25
𝑅𝐴 1
= 1
𝑅𝐵 2

/
𝑉2
P=
𝑅
Since V is same means P is inversely proportional to R.
Power of lamp A is double that of B hence Resistance of A is half that of
1
B.
𝑅𝐴 1
= 1
𝑅𝐵 2
OR
(b)
𝑉2 ½
H= ×𝑡
𝑅
𝑉2
400= × 1 ½
4

𝑉 2 =1600
V=40V 1
2
23.

diagram 1
labelling 1 2
24. (a)
• Plugging of the leak in blood vessels prevents lowering of the
blood pressure / maintains the efficiency of the pumping system. 1

• Platelets ½
• Help to clot the blood at the site of injury. ½
OR
(b)
(i) Plants have low energy needs because they have a large
proportion of dead cells in many tissues / Plants have low 1
energy needs as they do not move

(ii) Translocation of soluble products of photosynthesis from
leaves to other parts of the plant / It transports amino acids 1
and other substances to storage organs of roots, fruits and
seeds and to growing organs. 2

Page 4 of 11 X_086_31/1/3

25. • Evolution of gas 1
• Change / Rise in temperature 1 2
26. (a) 2 𝐻𝑁𝑂3 + 𝐶𝑎(𝑂𝐻)2 → 𝐶𝑎(𝑁𝑂3 )2 + 2 𝐻2 𝑂 1

(b) 𝑁𝑎𝐶𝑙 + 𝐴𝑔𝑁𝑂3 → 𝐴𝑔𝐶𝑙 + 𝑁𝑎𝑁𝑂3 1 2
(Deduct half mark if equation is not balanced)
SECTION C
27. (a) It is the amount of work done to bring one coulomb charge from
1𝐽 1
one point to another in the field is 1 joule. / 1V=
1𝐶

(b)

1

𝑷𝒐𝒕𝒆𝒏𝒕𝒊𝒂𝒍 𝒅𝒊𝒇𝒇𝒆𝒓𝒆𝒏𝒄𝒆 𝟏⋅𝟓 𝑽
Current = =
𝑹𝒆𝒔𝒊𝒔𝒕𝒂𝒏𝒄𝒆 (𝟓 𝜴 + 𝟏𝟎 𝜴)

1⋅5 𝑉
= = 0·1 A 1
15 𝛺 3
28. (a)
1 1 1 1
= + =  R1 = 6 
𝑅1 10 𝛺 15 𝛺 6𝛺

1 1 1 100
= + =  R2 = 24 
𝑅2 60 𝛺 40 𝛺 2400 𝛺

∵ R1 and R2 are in series

1
 Rtotal = R1 + R2 = (6 + 24) = 30 

𝑉 15 𝑉
(b) V = IR  I= = = 0·5 A 1
𝑅 30 𝛺

(c) V = IR1 = 0·5 A  6  = 3·0 V 1 3

Page 5 of 11 X_086_31/1/3

29. (i)
IMAGE

1½

OBJECT
(ii)

1½

(Note: Deduct ½ mark if arrows are not drawn.) 3
30. (a)
• 23 pairs or 46 chromosomes ½
• 1 Pair or 2 chromosomes ½

(b) In sexually reproducing organisms chromosomes occur
in pairs. The members of the pair separate at the time of
gamete formation. The two germ cells fuse and form 2

zygote thus restore the same number of chromosomes as their
parents.
(Award marks if explained by any other method.)
3
31. (a) Adrenaline ½
Adrenal Gland ½
(b) It acts on heart. Heart beats faster, resulting in more
supply of oxygen to skeletal muscles. The blood to the
digestive system and skin is reduced due to contraction of
2
muscles around small arteries in these organs. Breathing rate
increases because of contraction of diaphragm and the rib
muscles. 3
32. (a)
➢ Take three test tubes and place clean iron nails in each of them.
➢ Label these test tubes A, B and C.

Page 6 of 11 X_086_31/1/3

➢ Pour some water in test tube A and cork it.
➢ Pour boiled distilled water in test tube B, add about 1 mL of oil
and cork it. The oil will float on water and prevent the air from
dissolving in the water.
➢ Put some anhydrous calcium chloride in test tube C and cork it.
Anhydrous calcium chloride will absorb the moisture, if any, from
the air.
Iron nails rust in test tube A, but they do not rust in test tubes B and
C.
Rusting of iron takes place when exposed to both air and water.
/
3

Iron nails rust in test tube A, but they do not rust in test tubes B and
C.
Rusting of iron takes place when exposed to both air and water.

(Note: if a student explains activity through description or through
labelled diagram, give full marks.)
OR

(b) (i)
• Sodium, Potassium, Lithium ½,½
(any two)
• Observations:
➢ A violent reaction occurs. 1½
➢ Large amount of heat is evolved.
➢ Evolved gas catches fire.

(ii) The gas (bubbles) burns with a pop sound ½ 3
33. (a)
3 𝑀𝑛𝑂2 (𝑠) + 4 𝐴𝑙(𝑠) → 3 𝑀𝑛(𝑙) + 2 𝐴𝑙2 𝑂3 (𝑠) + ℎ𝑒𝑎𝑡
1
𝐹𝑒2 𝑂3 (𝑠) + 2 𝐴𝑙(𝑠) → 2 𝐹𝑒(𝑙) + 𝐴𝑙2 𝑂3 (𝑠) + ℎ𝑒𝑎𝑡 1
(Award marks if explained through statement)
(b)
Metals towards the top of the reactivity series (Na, Mg, Ca) have more 1 3
affinity for oxygen than carbon.
SECTION D
34. (a) (i)
• Concave lens ½

Page 7 of 11 X_086_31/1/3

1
• P= ½
𝑓(𝑚)
1
– 25 =
𝑓
10 ½
f= = – 0·4 m = – 40 cm
– 2⋅5
• Myopia ½
(ii) (I) Real and inverted ½×4
(II) magnified image /size of image is
double the size of object
(III) beyond 2F/ on the other side as that of object
(IV) Negative
(iii)
• The lens with focal length 10 cm ½
• less focal length, more converging/diverging power ½
OR
(b) (i)

2

( if arrows not marked , deduct half mark)

(ii) The ratio of sine of angle of incidence to the sine
of angle of refraction is a constant, for the light of a
given colour and for a given pair of media. / 1

(iii)

Convex Lens Concave Lens 1
(I) Object to be placed between Object can be placed anywhere
O and F in front of the lens 1 5
(II) Magnified image Diminished image
35. (a) (i)
(I) Ovary: Produces female gamete (egg) and female ½,½
hormones(oestrogen).
(II) Fallopian tube: Site of Fertilization 1
(III) Uterus: Site of implantation and embryonic development. 1

(ii) Methods of contraception used by males: 1
• Mechanical barrier - Condoms

Page 8 of 11 X_086_31/1/3