CBSE Class 10 Science Question Paper 2020 Set 31-4-3

H$moS> Z§.
Code No. 31/4/3
amob Z§. narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð
Roll No. >na Adí` {bIo§ &
Candidates must write the Code on the
title page of the answer-book.

ZmoQ> NOTE
(I) H¥$n`m Om±M H$a b| {H$ Bg àíZ-nÌ _o§ _w{ÐV (I) Please check that this question
n¥ð> 23 h¢ & paper contains 23 printed pages.

(II) àíZ-nÌ _| Xm{hZo hmW H$s Amoa {XE JE H$moS (II) Code number given on the right
>Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na hand side of the question paper
{bI| & should be written on the title page of
the answer-book by the candidate.
(III) H¥$n`m Om±M H$a b| {H$ Bg àíZ-nÌ _| (III) Please check that this question
>30 àíZ h¢ & paper contains 30 questions.
(IV) H¥$n`m àíZ H$m CÎma {bIZm ewê$ H$aZo go (IV) Please write down the serial number
nhbo, CÎma-nwpñVH$m _| àíZ H$m H«$_m§H$ of the question in the answer-book
Adí` {bI| & before attempting it.
(V) Bg àíZ-nÌ H$mo n‹T>Zo Ho$ {bE 15 {_ZQ >H$m (V) 15 minute time has been allotted to
g_` {X`m J`m h¡ & àíZ-nÌ H$m {dVaU read this question paper. The
nydm©• _| 10.15 ~Oo {H$`m OmEJm & question paper will be distributed
10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db at 10.15 a.m. From 10.15 a.m. to
10.30 a.m., the students will read the
àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg Ad{Y Ho$ Xm¡amZ question paper only and will not
do CÎma-nwpñVH$m na H$moB© CÎma Zht {bI|Jo & write any answer on the
answer-book during this period.

{dkmZ
SCIENCE

{ZYm©[aV g_` : 3 KÊQ>o A{YH$V_ A§H$ : 80
Time allowed : 3 hours Maximum Marks : 80

.31/4/3 1 P.T.O.

gm_mÝ` {ZX}e :
{ZåZ{b{IV {ZX}em| H$mo ~hþV gmdYmZr go n{‹T>E Am¡a CZH$m g™Vr go nmbZ H$s{OE :
(i) `h àíZ-nÌ VrZ IÊS>m| _§o {d^m{OV {H$`m J¶m h¡ — H$, I Am¡a J & Bg àíZ-nÌ _| àíZm|
H$s g§»`m 30 h¡ & g^r àíZ A{Zdm`© h¢ &
(ii) IÊS> H$ Ho$ g^r àíZ/CZHo$ ^mJ, àíZ g§»`m 1 go 14 VH$ EH$-EH$ A§H$ Ho$ h¢ & BZ àíZm|
_| ~hþ{dH$ënr àíZ, A{V bKw-CÎmar` àíZ VWm A{^H$WZ-H$maU àH$ma Ho$ àíZm| H$mo
gpå_{bV {H$`m J`m h¡ & BZ àíZm| Ho$ CÎma EH$ eãX AWdm EH$ dmŠ` _| {XE OmZo Mm{hE &
(iii) IÊS> I _| àíZ g§»`m 15 go 24 VH$ bKw-CÎmar` àH$ma Ho$ àíZ h¢, àË`oH$ àíZ 3 A§H$
H$m h¡ & BZ àíZm| H$m CÎma 50 go 60 eãXm| go A{YH$ Zht hmoZm Mm{hE &
(iv) IÊS> J _| àíZ g§»`m 25 go 30 VH$ XrK©-CÎmar` àH$ma Ho$ àíZ h¢, àË`oH$ àíZ 5 A§H$
H$m h¡ & BZ àíZm| H$m CÎma 80 go 90 eãXm| go A{YH$ Zht hmoZm Mm{hE &
(v) CÎma g§{já VWm q~Xþdma hmoZo Mm{hE Am¡a gmW hr Cn`w©º$ eãX gr_m H$m `Wmg§^d nmbZ
{H$`m OmZm Mm{hE &
(vi) àíZ-nÌ _| g_J« na H$moB© {dH$ën Zht h¡ & VWm{n àË`oH$ IÊS> _| Hw$N> àíZm| _| Am§V[aH$
{dH$ën {XE JE h¢ & Eogo àíZm| _§o go Ho$db EH$ hr {dH$ën H$m CÎma {b{IE &
(vii) BgHo$ A{V[aº$, Amdí`H$VmZwgma, àË`oH$ IÊS> Am¡a àíZ Ho$ gmW `Wmo{MV {ZX}e {XE JE h¢ &

IÊS> H$
1. {H$gr Eogo H$m~m}pŠg{bH$ Aåb H$s g§aMZm It{ME {Og_| VrZ H$m~©Z na_mUw hmoVo h¢ & 1

2. {H$gr Ymamdmhr MmbH$ Ho$ Xmo {~ÝXþAm| Ho$ ~rM {d^dmÝVa 1 dmoëQ> H$~ H$hm OmVm h¡ ? 1

3. {ZåZ{b{IV AZwÀN>oX Am¡a n‹T>r J`t g§~§{YV g§H$ënZmAm| H$s ì`m»`m Ho$ AmYma na àíZ
g§»`m 3(a) go 3(d) Ho$ CÎma Xr{OE :
gZ² 1800 Ho$ bJ^J VH$ Ho$db 30 VÎd hr kmV Wo & 1817 _| S>m°~oamBZa Am¡a
1866 _| Ý`yb¢S²>g Zo V~ VH$ kmV VÎdm| H$mo ì`dpñWV H$aZo Ho$ {bE à`mg {H$E Am¡a Hw$N>
{Z`_ ~ZmE {OÝh| d¡km{ZH$m| Zo AñdrH$ma H$a {X`m & CZ àñVm{dV {Z`_m| Ho$ AñdrH$ma
{H$E OmZo Ho$ níMmV² ^r H$B© d¡km{ZH$m| Zo Eogo à{Vê$nm| H$s ImoO Omar aIr {Oggo VÎdm| Ho$
JwUY_m] H$m CZHo$ na_mUw Ðì`_mZm| Ho$ gmW g§~§Y ñWm{nV hmo gHo$ &

.31/4/3 2

General Instructions :
Read the following instructions very carefully and strictly follow them.
(i) This question paper comprises three Sections — A, B and C. There are
30 questions in the question paper. All questions are compulsory.
(ii) Section A – Questions no. 1 to 14 — all questions or part thereof are of
one mark each. These questions comprise Multiple Choice Questions
(MCQ), Very Short Answer (VSA) and Assertion–Reason type questions.
Answer to these questions should be given in one word or one sentence.
(iii) Section B – Questions no. 15 to 24 are short answer type questions,
carrying 3 marks each. Answer to these questions should not exceed 50 to
60 words.
(iv) Section C – Questions no. 25 to 30 are long answer type questions,
carrying 5 marks each. Answer to these questions should not exceed 80 to
90 words.
(v) Answers should be brief and to the point. Also the above mentioned word
limit be adhered to as far as possible.
(vi) There is no overall choice in the question paper. However, an internal
choice has been provided in some questions in each section. Only one of
the choices in such questions have to be attempted.
(vii) In addition to this, separate instructions are given with each section and
question, wherever necessary.

SECTION A

1. Draw the structure of a carboxylic acid containing three carbon atoms. 1

2. When is the potential difference between two points in a current carrying
conductor said to be 1 volt ? 1

3. Answer question numbers 3(a)  3(d) on the basis of your understanding
of the following paragraph and the related studied concepts :

Around the year 1800, only 30 elements were known. Dobereiner
in 1817 and Newlands in 1866 tried to arrange the then known elements
and framed laws which were rejected by the scientists. Even after the
rejection of the proposed laws, many scientists continued to search for a
pattern that correlated the properties of elements with their atomic
masses.

.31/4/3 3 P.T.O.

VÎdm| Ho$ dJuH$aU H$m _w»` lo` _oÝS>obr\$ H$mo OmVm h¡, {OÝhm|Zo VÎdm| H$s AmdV©
gmaUr Ho$ àma§{^H$ {dH$mg _| gdm©{YH$ _hÎdnyU© `moJXmZ {X`m & CÝhm|Zo VÎdm| H$mo CZHo$ _yb
JwUY_©, na_mUw Ðì`_mZ VWm amgm`{ZH$ JwUY_m] _| g_mZVm Ho$ AmYma na ì`dpñWV
{H$`m & CZHo$ hmBS´>mBS>m| Am¡a Am°ŠgmBS>m| Ho$ gyÌm| H$mo VÎdm| Ho$ dJuH$aU H$m _yb _mnXÊS>
_mZm J`m &
naÝVw _oÝS>obr\$ Ho$ dJuH$aU _| ^r Hw$N> H${_`m± Wt, Š`m|{H$ Bg_| g_ñWm{ZH$m| H$mo
H$moB© ñWmZ Zht {X`m J`m Wm & CÝhm|Zo AmdV© gmaUr _| Hw$N> [aº$ ñWmZ ^r N>mo‹S> {XE Wo &

3(a) _oÝS>obr\$ H$m AmdV© {Z`_ {b{IE & 1

3(b) _oÝS>obr\$ Zo AmdV© gmaUr _| Hw$N> [aº$ ñWmZ Š`m| N>mo‹S> {XE Wo ? 1

3(c) `{X {H$gr g_yh _| {H$gr VÎd H$mo ‘R’ Aja go {Zê${nV {H$`m OmVm h¡, Vmo H$m~©Z
Ho$ hmBS´>mBS> Am¡a Am°ŠgmBS> H$mo H«$_e: {H$g àH$ma {Zê${nV {H$`m OmEJm ? 1

(i) RH4, RO

(ii) RH4, RO2

(iii) RH2, RO2

(iv) RH2, RO

3(d) g_ñWm{ZH$ 1

(i) {H$gr VÎd Ho$ dh na_mUw h¢ {OZHo$ amgm`{ZH$ JwUY_© g_mZ naÝVw na_mUw
Ðì`_mZ {^Þ hmoVo h¢ &
(ii) {^Þ-{^Þ VÎdm| Ho$ dh na_mUw h¢ {OZHo$ amgm`{ZH$ JwUY_© g_mZ naÝVw
na_mUw Ðì`_mZ {^Þ hmoVo h¢ &
(iii) {H$gr VÎd Ho$ dh na_mUw h¢ {OZHo$ amgm`{ZH$ JwUY_© {^Þ naÝVw na_mUw
Ðì`_mZ g_mZ hmoVo h¢ &
(iv) {^Þ-{^Þ VÎdm| Ho$ dh na_mUw h¢ {OZHo$ amgm`{ZH$ JwUY_© {^Þ naÝVw
na_mUw Ðì`_mZ g_mZ hmoVo h¢ &
.31/4/3 4

The main credit for classifying elements goes to Mendeleev for his
most important contribution to the early development of a Periodic table
of elements wherein he arranged the elements on the basis of their
fundamental property, the atomic mass and also on the similarity of
chemical properties. The formulae of their hydrides and oxides were
treated as basic criteria for the classification of the elements.

However, Mendeleev’s classification also had some limitations as it
could not assign the position to isotopes. He also left some gaps in the
periodic table.

3(a) State Mendeleev’s Periodic Law. 1

3(b) Why did Mendeleev leave some gaps in the Periodic table ? 1

3(c) If the letter ‘R’ was used to represent any of the elements in the
group, then the hydride and oxide of carbon would respectively be
represented as 1
(i) RH4, RO

(ii) RH4, RO2

(iii) RH2, RO2

(iv) RH2, RO

3(d) Isotopes are 1

(i) Atoms of an element with similar chemical properties but
different atomic masses.

(ii) Atoms of different elements with similar chemical properties
but different atomic masses.

(iii) Atoms of an element with different chemical properties but
same atomic masses.

(iv) Atoms of different elements with different chemical
properties but same atomic masses.

.31/4/3 5 P.T.O.

4. {ZåZ{b{IV AZwÀN>oX Am¡a n‹T>r J`t g§~§{YV g§H$ënZmAm| H$s ì`m»`m Ho$ AmYma na àíZ
g§»`m 4(a) go 4(d) Ho$ CÎma Xr{OE :
^maV AmO g§gmYZm| Ho$ AË`{YH$ XmohZ, Ob Am¡a _¥Xm Ho$ g§XÿfU VWm H$Mao H$mo
g§gm{YV H$aZo H$s {d{Y`m| H$s H$_r H$s g_ñ`m H$m gm_Zm H$a ahm h¡ & A~ g_` Am J`m
h¡ {H$ g§gma ‘‘EH$b-Cn`moJ ßbmpñQ>H$’’ H$mo {dXm H$ho & BgHo$ n`m©daU-{hV¡fr {dH$ënm|,
An{eîQ> ßbmpñQ>H$ H$m à^mdr EH$ÌrH$aU Am¡a CgH$m {ZnQ>mam H$aZo H$s {d{Y`m± {dH${gV
H$aZo Ho$ {bE à`mg {H$E OmZo Mm{hE &
BÝXm¡a Zo _mÌ 3 df© _| O¡d-IZZ Am¡a O¡d-CnMm`© H$s à{H«$`mAm| Ûmam 15 bmI
_r{Q´>H$ Q>Z H$Mao H$mo g§gm{YV {H$`m h¡ & O¡d-CnMm`© _| {H$gr b¡ÊS>{\$b _| OrdmUwAm| H$mo
S>mbH$a H$Mao H$mo àmH¥${VH$ ê$n go ‘AnK{Q>V’ {H$`m OmVm h¡ VWm O¡d-IZZ _| Q´>mo_b
_erZm| Ûmam H$Mao H$mo N>mZH$a ‘_¥Xm’ H$mo H$Mao go n¥WH²$ {H$`m OmVm h¡ & Bg eha Zo bJ^J
10 H$amo‹S> én`o IM© H$aHo$ 15 bmI _r{Q´>H$ Q>Z H$Mao H$m {ZnQ>mam H$aZo _| g\$bVm nmB© &
Eogm hr EH$ g\$b à`moJ Ah_Xm~mX _| ^r {H$`m J`m &
4(a) AnZo {dÚmb` _| An{eîQ> ßbmpñQ>H$ H$mo EH$Ì H$aZo H$s Xmo à^mdr {d{Y`m| H$m
CëboI H$s{OE & 1

4(b) ‘‘EH$b-Cn`moJ ßbmpñQ>H$’’ Ho$ X¡{ZH$ OrdZ _| H$moB© Xmo Cn`moJ {b{IE & 1

4(c) `{X ßbmpñQ>H$ H$m Cn`moJ amoH$ {X`m OmE, Vmo BgHo$ ñWmZ na H$moB© n`m©daU-{hV¡fr
{dH$ën H¡$go àXmZ {H$`m Om gH$Vm h¡ ? 1

4(d) Š`m Amn Eogm gmoMVo h¢ {H$ b¡ÊS>{\$b ñWb _| OrdmUw Cgr àH$ma H$m`© H$a|Jo O¡gm
do à`moJembm _| H$aVo h¢ ? AnZo CÎma H$s nw{îQ> H$s{OE & 1

5. {ZåZ{b{IV _| go AgË` H$WZ Mw{ZE : 1

(A) Am°ŠgrOZ Ho$ VrZ na_mUwAm| go AmoµOmoZ H$m EH$ AUw ~ZVm h¡ &
(B) AmoµOmoZ nam~¢JZr {d{H$aUm| go n¥Ïdr Ho$ n¥îR> H$s gwajm H$aVr h¡ &
(C) AmoµOmoZ AË`ÝV {df¡br hmoVr h¡ &
(D) AmoµOmoZ nam~¢JZr {d{H$aUm| Ûmam AnK{Q>V ({d`mo{OV) hmo OmVr h¡ &
.31/4/3 6

4. Answer question numbers 4(a)  4(d) on the basis of your understanding
of the following paragraph and the related studied concepts :

India today is facing the problem of overuse of resources,
contamination of water and soil and lack of methods of processing the
waste. The time has come for the world to say goodbye to ‘‘single-use
plastics’’. Steps must be undertaken to develop environment-friendly
substitutes, effective plastic waste collection and methods of its disposal.

Indore treated 15 lakh metric tonnes of waste in just 3 years,
through biomining and bioremediation techniques. Bioremediation
involves introducing microbes into a landfill to naturally ‘break’ it down
and biomining involves using trommel machines to sift through the waste
to separate the ‘soil’ and the waste component. The city managed to chip
away 15 lakh metric tonnes of waste at a cost of around < 10 crore. A
similar experiment was successfully carried out in Ahmedabad also.

4(a) State two methods of effective plastic waste collection in your
school. 1

4(b) Name any two uses of ‘‘single-use plastic’’ in daily life. 1

4(c) If we discontinue the use of plastic, how can an
environment-friendly substitute be provided ? 1

4(d) Do you think microbes will work similarly in landfill sites as they
work in the laboratory ? Justify your answer. 1

5. Choose the incorrect statement from the following : 1

(A) Ozone is a molecule formed by three atoms of oxygen.

(B) Ozone shields the surface of the Earth from ultraviolet radiations.
(C) Ozone is deadly poisonous.

(D) Ozone gets decomposed by UV radiations.

.31/4/3 7 P.T.O.

6. Amhma Omb ~ZVm h¡ 1
(A) Ordm| Am¡a n`m©daU Ho$ ~rM g§~§Y Ûmam
(B) nmXnm| Am¡a OÝVwAm| Ho$ ~rM g§~§Y Ûmam
(C) {H$gr nm[aV§Ì _| {d{^Þ Amhma ûm¥§IbmAm| Ho$ Omo‹S> go
(D) OÝVwAm| Am¡a n`m©daU Ho$ ~rM g§~§Y Ûmam
7. ‘hmBS´>m’ _| ‘_wHw$b’ Ho$ ~mao _| {ZåZ{b{IV _| go H$m¡Z-gm H$WZ ghr Zht h¡ ? 1
(A) `h H$moB© C^ma And¥Õ h¡ &
(B) `h {H$gr {d{eîQ> ñWb na H$mo{eH$m {d^mOZ H$s nwZamd¥{Îm Ho$ H$maU ~ZVm h¡ &
(C) O¡go hr `h CËnÞ hmoVm h¡ `h OZH$ H$m` go AbJ hmo OmVm h¡ &
(D) `h EH$ Z`m ñdV§Ì ì`{îQ> ~Z OmVm h¡ &
8. Adm`dr` à{H«$`m 1
(A) {H$ÊdZ Ho$ g_` `rñQ> _| hmoVr h¡ &
(B) Am°ŠgrOZ H$s CnpñW{V _| hmoVr h¡ &
(C) _mZdm| H$s no{e`m| _| Ho$db D$Om© CËnÞ H$aVr h¡ &
(D) _| EWoZm°b, Am°ŠgrOZ Am¡a D$Om© CËnÞ hmoVr h¡ &
AWdm
^moOZ H$m A{YH$m§e nmMZ Am¡a AdemofU H$hm± hmoVm h¡ ? 1
(A) jwÐm§Ì _|
(B) `H¥$V _|
(C) Am_me` _|
(D) ~¥hÐm§Ì _|
9. {ZåZ{b{IV _| go H$m¡Z-gm {dÚwV² e{º$ H$mo {Zê${nV Zht H$aVm ? 1

(A) I2R

(B) IR2
(C) VI

(D) V2/R
.31/4/3 8

6. Food web is constituted by 1
(A) relationship between the organisms and the environment.
(B) relationship between plants and animals.
(C) various interlinked food chains in an ecosystem.
(D) relationship between animals and environment.

7. Which of the following statements is not true about a ‘bud’ in ‘Hydra’ ? 1
(A) It is an outgrowth.
(B) It forms due to repeated cell division at one specific site.
(C) It detaches from the parent body as soon as it is produced.
(D) It becomes a new independent individual.

8. Anaerobic process 1
(A) takes place in yeast during fermentation.
(B) takes place in the presence of oxygen.
(C) produces only energy in the muscles of human beings.
(D) produces ethanol, oxygen and energy.

OR
Most of the digestion and absorption of the food takes place in the 1
(A) small intestine.
(B) liver.
(C) stomach.
(D) large intestine.

9. Which of the following does not represent electrical power ? 1

(A) I2R

(B) IR2
(C) VI

(D) V2/R

.31/4/3 9 P.T.O.

10. {H$gr Zm{^H$s` [aEoŠQ>a _| Zm{^H$s` D$Om© CËnÞ H$aZo Ho$ ~mao _| {ZåZ{b{IV _| go H$m¡Z-gm
H$WZ gË` Zht h¡ ? 1
(A) Bg_| D$Om© Zm{^H$s` {dIÊS>Z H$s à{H«$`m Ûmam àmßV hmoVr h¡ &
(B) Bg_| `yao{Z`_ Ho$ Zm{^H$ na CÀM D$Om© dmbo Ý`yQ´>m°Zm| H$s ~_~mar H$s OmVr h¡ &
(C) Bg à{H«$`m _| ûm¥§Ibm A{^{H«$`m hmoVr h¡ &
(D) Bg à{H«$`m _| {Z`§{ÌV Xa na {demb _mÌm _| D$Om© _wº$ hmoVr h¡ &
AWdm
n¥Ïdr Ho$ n¥îR> na D$Om© H$m g~go ~‹S>m òmoV h¡ 1
(A) O¡d_mÌm (~m`mo_mg)
(B) gm¡a {d{H$aU
(C) Ádma-^mQ>m
(D) ndZ
11. _mZd n[ag§MaU V§Ì Ho$ {df` _| {ZåZ{b{IV _| go H$m¡Z-gm H$WZ ghr h¡ ? 1
(A) é{Ya Ho$db Am°ŠgrOZ H$m dhZ H$aVm h¡ VWm H$m~©Z S>mBAm°ŠgmBS> H$m dhZ Zht
H$aVm &
(B) _mZd öX` _| nm±M H$moîR> hmoVo h¢ &
(C) dmëd é{Ya Ho$ níM àdmh na amoH$ H$mo gw{ZpíMV H$aVo h¢ &
(D) öX` _| Am°ŠgrOZ-~hþb Am¡a Am°ŠgrOZ-Ý`yZ XmoZm| é{Ya {_{lV hmoVo h¢ &

12. `{X {H$gr ì`{º$ Ho$ nmg nm±M à{VamoYH$ h¢ {OZ_| àË`oH$ H$m à{VamoY 1  h¡, Vmo dh BÝh|
5
g§`mo{OV H$aHo$ {H$VZm A{YH$V_ à{VamoY àmßV H$a gH$Vm h¡ ? 1
(A) 1
(B) 5
(C) 10 
(D) 25 

AWdm
{H$gr à{VamoYH$ H$m à{VamoY CgHo$ àmapå^H$ _mZ H$m AmYm H$a {X`m J`m h¡ & Eogm H$aZo
_|, `{X n[anW Ho$ AÝ` àmMbm| H$mo n[ad{V©V Z {H$`m OmE, Vmo Bg à{VamoYH$ _| VmnZ
à^md hmo OmEJm 1
(A) XþJwZm
(B) AmYm
(C) EH$-Mm¡WmB©
(D) Mma JwZm
.31/4/3 10

10. Which one of the following statements is not true about nuclear energy
generation in a nuclear reactor ? 1
(A) Energy is obtained by a process called nuclear fission.
(B) The nucleus of Uranium is bombarded with high energy neutrons.
(C) A chain reaction is set in the process.
(D) In this process a tremendous amount of energy is released at a
controlled rate.
OR
The biggest source of energy on Earth’s surface is 1
(A) Biomass
(B) Solar radiations
(C) Tides
(D) Winds
11. Which one of the following statements is correct about the human
circulatory system ? 1
(A) Blood transports only oxygen and not carbon dioxide.
(B) Human heart has five chambers.
(C) Valves ensure that the blood does not flow backwards.
(D) Both oxygen-rich and oxygen-deficient blood gets mixed in the
heart.

1
12. If a person has five resistors each of value , then the maximum
5
resistance he can obtain by connecting them is 1
(A) 1
(B) 5
(C) 10 
(D) 25 
OR
The resistance of a resistor is reduced to half of its initial value. In doing
so, if other parameters of the circuit remain unchanged, the heating
effects in the resistor will become 1
(A) two times.
(B) half.
(C) one-fourth.
(D) four times.
.31/4/3 11 P.T.O.

àíZ g§»`m 13 Am¡a 14 Ho$ {bE, Xmo H$WZ {XE JE h¢ {OZ_| EH$ H$mo A{^H$WZ (A) VWm Xÿgao
H$mo H$maU (R) Ûmam A§{H$V {H$`m J`m h¡ & BZ àíZm| Ho$ ghr CÎma ZrMo {XE JE H$moS>m| (a),
(b), (c) Am¡a (d) _| go MwZH$a Xr{OE &

(a) (A) Am¡a (R) XmoZm| ghr h¢ Am¡a (R), A{^H$WZ (A) H$s ghr ì`m»`m H$aVm h¡ &

(b) (A) Am¡a (R) XmoZm| ghr h¢, naÝVw (R), A{^H$WZ (A) H$s ghr ì`m»`m Zht H$aVm
h¡ &

(c) (A) ghr h¡, naÝVw (R) µJbV h¡ &

(d) (A) µJbV h¡, naÝVw (R) ghr h¡ &

13. A{^H$WZ (A) : _mZdm| _| {H$gr {eew H$m qbJ CgHo$ {nVm Ûmam d§emZwJV JwUgyÌ Ho$
àH$ma Ûmam {ZYm©[aV hmoVm h¡ &

H$maU (R) : dh {eew Omo AnZo {nVm go ‘X’ JwUgyÌ d§emZwJV H$aVm h¡ b‹S>H$s (XX)
hmoVr h¡ O~{H$ dh {eew Omo AnZo {nVm go ‘Y’ JwUgyÌ d§emZwJV H$aVm h¡
b‹S>H$m (XY) hmoVm h¡ & 1

14. A{^H$WZ (A) : {ZåZ{b{IV g§Vw{bV amgm`{ZH$ g_rH$aU Am`aZ na ^mn H$s {H«$`m Ho$
{bE h¡ :
3Fe + 4H2O  Fe3O4 + 4H2

H$maU (R) : {H$gr amgm`{ZH$ g_rH$aU na Ðì`_mZ Ho$ g§ajU H$m {Z`_ bmJy hmoVm
h¡ & 1

.31/4/3 12

For question numbers 13 and 14, 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 (A) and (R) are true and (R) is the correct explanation of the
assertion (A).

(b) Both (A) and (R) are true, but (R) is not the correct explanation of
the assertion (A).

(c) (A) is true, but (R) is false.

(d) (A) is false, but (R) is true.

13. Assertion (A) : The sex of a child in human beings will be determined by
the type of chromosome he/she inherits from the father.

Reason (R) : A child who inherits ‘X’ chromosome from his father
would be a girl (XX), while a child who inherits a
‘Y’ chromosome from the father would be a boy (XY). 1

14. Assertion (A) : Following is a balanced chemical equation for the action
of steam on iron :

3Fe + 4H2O  Fe3O4 + 4H2

Reason (R) : The law of conservation of mass holds good for a chemical
equation. 1

.31/4/3 13 P.T.O.

IÊS> I
15. JwéËdmZwdV©Z H$s n[a^mfm {b{IE & {H$gr nmXn Ho$ ^mJm| _| JwéËdmZwdVu J{V`m| H$mo Xem©Zo
Ho$ {bE Zm_m§{H$V AmaoI It{ME & 3

16. H$moB© MrVm, AnZo {eH$ma H$mo XoIH$a, CgH$s Amoa AË`{YH$ Vrd« J{V go Xm¡‹S>Vm h¡ & CgH$s
no{e`m| H$mo {H$g àH$ma J{V {_bVr h¡ ? Bg n[aKQ>Zm Ho$ g_` no{e`m| Ho$ H$mo{eH$s` Ad`dm|
Ho$ agm`Z _| Š`m n[adV©Z hmoVm h¡ ? 3

17. (a) g§KQ>Z _| gm~wZ, An_mO©H$ ({S>Q>aOoÝQ>) go {H$g àH$ma {^Þ hmoVm h¡ ?
(b) `h Xem©Zo Ho$ {bE {H$gr {H«$`mH$bmn H$s A{^H$ënZm H$s{OE {H$ g^r àH$ma Ho$
Ob Ho$ gmW An_mO©H$ ^br-^m±{V H$m`© H$aVo h¢ O~{H$ gm~wZ Eogm Zht H$aVo & 3

18. H$moB© naIZbr, {Og_| nmoQ>¡{e`_ Am`moS>mBS> H$m {db`Z ^am h¡, _| b¡S> ZmBQ´>oQ> {db`Z
{_bm`m J`m h¡ &
(a) Adjo{nV `m¡{JH$ H$m Zm_ Am¡a a§J {b{IE &
(b) hmoZo dmbr A{^{H«$`m H$m g§Vw{bV amgm`{ZH$ g_rH$aU {b{IE &
(c) Bg A{^{H«$`m Ho$ àH$ma H$m Zm_ {b{IE Am¡a AnZo CÎma H$s nw{îQ> H$s{OE & 3

AWdm
Š`m hmoVm h¡ O~ dgm VWm V¡br` ImÚ gm_J«r bå~o g_` VH$ aIr ah OmVr h¡ ? àojU
`mo½` Xmo n[adV©Zm| H$s gyMr ~ZmBE Am¡a Bg n[aKQ>Zm go ~Mmd Ho$ VrZ Cnm` gwPmBE & 3

19. `eXbonZ VWm {_lmËdZ H$s à{H«$`mAm| Ho$ ~rM VrZ {d^oXZH$mar bjUm| H$s gyMr ~ZmBE & 3

AWdm
Vm{bH$m Ho$ ê$n _| {ZåZ{b{IV YmVwAm| H$s R>§S>o Am¡a J_© Ob Ho$ gmW A{^{H«$`merbVmAm|
H$s VwbZm H$s{OE :
(a) gmo{S>`_
(b) H¡$pëg`_
(c) _¡½Zr{e`_ 3

.31/4/3 14

SECTION B

15. Define geotropism. Draw a labelled diagram of a plant showing geotropic
movements of its parts. 3

16. A cheetah, on seeing a prey, moves towards him at a very high speed.
What causes the movement of his muscles ? How does the chemistry of
cellular components of muscles change during this event ? 3
17. (a) How is a soap different from a detergent in composition ?

(b) Design an activity to show that a detergent works well with all
types of water while a soap does not. 3

18. Lead nitrate solution is added to a test tube containing potassium iodide
solution.

(a) Write the name and colour of the compound precipitated.

(b) Write the balanced chemical equation for the reaction involved.

(c) Name the type of this reaction justifying your answer. 3

OR
What happens when food materials containing fats and oils are left for a
long time ? List two observable changes and suggest three ways by which
this phenomenon can be prevented. 3

19. List three differentiating features between the processes of galvanisation
and alloying. 3
OR

Compare in tabular form the reactivities of the following metals with cold
and hot water :

(a) Sodium

(b) Calcium

(c) Magnesium 3

.31/4/3 15 P.T.O.

20. {d{^ÞVm nX H$s n[a^mfm {b{IE & ñnrerµO Ho$ {bE {d{^ÞVm bm^H$mar Š`m| hmoVr h¡ ?
b¢{JH$ OZZ Ûmam CËnÞ g§V{V _| {d{^ÞVmE± {XImB© XoZo Ho$ Xmo H$maUm| H$s gyMr ~ZmBE & 3

AWdm
AmZwd§{eH$ bjUm| Am¡a Cnm{O©V bjUm| Ho$ ~rM Xmo {d^oXZH$mar AÝVam| H$s gyMr ~ZmBE &
àË`oH$ àH$ma Ho$ {bE EH$ CXmhaU ^r Xr{OE & 3

21. Amn H$m±M Ho$ Xmo gd©g_ {àµÁ_m| H$m Cn`moJ {H$g àH$ma H$a|Jo {Oggo {H$ nhbo {àµÁ_ na
Amn{VV H$moB© nVbm ídoV àH$me nw§O Xÿgao {àµÁ_ go ídoV àH$me nw§O Ho$ ê$n _| hr {ZJ©V
hmo ? {H$aU AmaoI ItMH$a Cgo Zm_m§{H$V H$s{OE & 3

22. {H$gr AdVb Xn©U H$m Cn`moJ {H$gr {~å~ H$s {d{^Þ pñW{V`m| _| CgH$m à{V{~å~ ~ZmZo
Ho$ {bE {H$`m J`m h¡ & O~ `h {~å~ 15 cm \$moH$g Xÿar Ho$ AdVb Xn©U Ho$ Y«wd go
10 cm Xÿar na aIm h¡, Vmo Bg pñW{V _| {ZåZ{b{IV Ho$ {df` _| Š`m {ZîH$f© {ZH$mbo Om
gH$Vo h¢ ?
(a) à{V{~å~ H$s pñW{V
(b) à{V{~å~ H$m gmBµO
(c) à{V{~å~ H$s àH¥${V
AnZo {ZîH$fm] H$s nw{îQ> Ho$ {bE Zm_m§{H$V {H$aU AmaoI It{ME & 3

23. ZoÌ Ho$ {H$g Xmof H$mo XrK©-Ñ{îQ> Xmof (Xÿa-Ñ{îQ>Vm) H$hVo h¢ ? `h Xmof H$~ CËnÞ hmoVm h¡ ?
BgHo$ Xmo H$maU {b{IE & Bg Xmof H$m g§emoYZ {H$g àH$ma {H$`m OmVm h¡ ? 3

24. _mÜ`_ ‘x’ H$m _mÜ`_ ‘y’ Ho$ gmnoj AndV©Zm§H$ 2/3 h¡ VWm _mÜ`_ ‘y’ H$m _mÜ`_ ‘z’ Ho$
gmnoj AndV©Zm§H$ 4/3 h¡ & _mÜ`_ ‘x’ Ho$ gmnoj _mÜ`_ ‘z’ H$m AndV©Zm§H$ kmV H$s{OE &
`{X _mÜ`_ ‘x’ _| àH$me H$s Mmb 3  108 ms1 h¡, Vmo _mÜ`_ ‘y’ _| àH$me H$s Mmb
n[aH${bV H$s{OE & 3

.31/4/3 16

20. Define the term variation. Why is variation beneficial to a species ? List
two reasons for the appearance of variations among the progeny formed
by sexual reproduction. 3
OR

List two distinguishing features between inherited and acquired
characters. Also give one example for each type. 3

21. How will you use two identical glass prisms so that a narrow beam of
white light incident on one prism emerges out of the second prism as
white light ? Draw and label the ray diagram. 3

22. A concave mirror is used for image formation for different positions of an
object. What inferences can be drawn about the following when an object
is placed at a distance of 10 cm from the pole of a concave mirror of focal
length 15 cm ?

(a) Position of the image

(b) Size of the image

(c) Nature of the image

Draw a labelled ray diagram to justify your inferences. 3

23. Which defect of the eye is known as far-sightedness ? When does this
defect arise ? State two reasons. How is this defect corrected ? 3

24. The refractive index of a medium ‘x’ with respect to a medium ‘y’ is 2/3
and the refractive index of medium ‘y’ with respect to medium ‘z’ is 4/3.
Find the refractive index of medium ‘z’ with respect to medium ‘x’. If the
speed of light in medium ‘x’ is 3  108 ms1, calculate the speed of light
in medium ‘y’. 3

.31/4/3 17 P.T.O.

IÊS> J

25. ß`mµO Ho$ ag _| {^JmoH$a {ZH$mbr JB© H$n‹S>o H$s {H$gr nÅ>r H$m Cn`moJ {H$gr Ðd ‘X’ Ho$
narjU Ho$ {bE {H$`m J`m & Ðd ‘X’ Zo CgH$s J§Y H$mo n[ad{V©V H$a {X`m & ß`mµO H$m ag
{H$g àH$ma H$m gyMH$ h¡ ? `hr Ðd ‘X’ Zrbo {bQ>_g H$mo bmb H$a XoVm h¡ & {ZåZ{b{IV Ho$
gmW Ðd ‘X’ H$s A{^{H«$`m Ho$ àojUm| H$mo Xem©Zo Ho$ {bE gyMr ~ZmBE :
(a) qµOH$ H$s H${UH$mE±
(b) R>mog gmo{S>`_ H$m~m}ZoQ>
hmoZo dmbr A{^{H«$`mAm| Ho$ amgm`{ZH$ g_rH$aU {b{IE & 5

AWdm

{H$ñQ>bZ Ob H$s n[a^mfm {b{IE & CXmhaUm| Ho$ ê$n _| Xmo `m¡{JH$m| Ho$ amgm`{ZH$ gyÌ
{b{IE & `h {H$g àH$ma gË`m{nV {H$`m Om gH$Vm h¡ {H$ {H«$ñQ>bZ Ob `m¡{JH$m| H$s
AdñWm Am¡a a§J _| AÝVa H$a gH$Vm h¡ ? 5

26. (a) ‘{_lmVw’ Am¡a ‘A_bJ_’ nXm| H$s n[a^mfm {b{IE & {dÚwV² Vmam| H$mo Amng _|
Omo‹S>Zo (doëS>Z) _| Cn`moJ hmoZo dmbr {_lmVw H$m Zm_ {b{IE Am¡a BgHo$ g§KQ>H$m|
H$m CëboI H$s{OE &

(b) {ZåZ{b{IV {_lmVwwAm| Ho$ g§KQ>H$m| Ho$ Zm_ {b{IE :
(i) nrVb (~«mg)
(ii) ñQ>oZbog ñQ>rb (BñnmV)
(iii) ~«m±O (H$m±gm)
BZ {_lmVwAm| _| àË`oH$ H$m EH$ Eogm JwUY_© {b{IE Omo Cg_| AnZo g§KQ>H$m| go
{^Þ h¡ & 5

.31/4/3 18

SECTION C

25. A cloth strip dipped in onion juice is used for testing a liquid ‘X’. The
liquid ‘X’ changes its odour. Which type of an indicator is onion juice ?
The liquid ‘X’ turns blue litmus red. List the observations the liquid ‘X’
will show on reacting with the following :

(a) Zinc granules

(b) Solid sodium carbonate

Write the chemical equations for the reactions involved. 5

OR

Define water of crystallisation. Give the chemical formula for two
compounds as examples. How can it be proved that the water of
crystallisation makes a difference in the state and colour of the
compounds ? 5

26. (a) Define the terms ‘alloy’ and ‘amalgam’. Name the alloy used for
welding electric wires together and write its constituents.

(b) Name the constituents of the following alloys :

(i) Brass

(ii) Stainless steel

(iii) Bronze

State one property in each of these alloys which is different from
its constituents. 5

.31/4/3 19 P.T.O.

27. (a) âboq_J H$m dm_-hñV {Z`_ {b{IE &
(b) h_ AnZo Kam| _| {Og {dÚwV² Ymam H$m Cn`moJ H$aVo h¢ CgHo$ VrZ {d{eîQ> bjUm|
H$s gyMr ~ZmBE &
(c) â`yµO Š`m hmoVm h¡ ? Bgo gwajm `w{º$ Š`m| H$hVo h¢ ?
(d) YmVw Ho$ AmdaU dmbo {dÚwV² gm{YÌm| H$mo ^ygån{H©$V H$aZm Š`m| Amdí`H$ h¡ ? 5

28. (a) {H$gr _mZd _mXm Ho$ J^m©e` _| AÊS> Ho$ {ZfoMZ go {eew Ho$ OÝ_ VH$ hmoZo dmbr
KQ>ZmAm| H$s H«$_dma gyMr ~ZmBE &
(b) O~ AÊS> H$m {ZfoMZ Zht hmoVm h¡ Vmo Cg pñW{V _| J^m©e` _| {XImB© XoZo dmbo
n[adV©Zm| H$m CëboI H$s{OE & 5

AWdm
(a) H$m{`H$ àdY©Z {H$go H$hVo h¢ ? BgHo$ VrZ bm^m| H$s gyMr ~ZmBE & H$m{`H$ àdY©Z
Ûmam ZE nm¡Yo CJmZo H$s Xmo {d{Y`m| H$m Zm_ {b{IE &

(b) H$maU XoVo hþE ì`m»`m H$s{OE {H$ A{YH$ O{Q>b Ord nwZéX²^dZ (nwZO©ZZ) Ûmam
ZB© g§V{V CËnÞ Š`m| Zht H$a gH$Vo & 5

29. (a) _mZd eara Ho$ {bE nmofU Š`m| Amdí`H$ h¡ ?

(b) Amhma Zmb Ho$ ^rVa ^moOZ H$mo H$m¡Z J{V àXmZ H$aVm h¡ ?

(c) _m§gmhm[a`m| H$s VwbZm _| emH$mhm[a`m| H$s jwÐm§Ì A{YH$ bå~r Š`m| hmoVr h¡ ?

(d) `{X OR>a J«§{W`m± íboî_m H$m òdU Z H$a|, Vmo Š`m hmoJm ? 5

.31/4/3 20

27. (a) State Fleming’s Left-hand rule.

(b) List three characteristic features of the electric current used in our
homes.

(c) What is a fuse ? Why is it called a safety device ?

(d) Why is it necessary to earth metallic electric appliances ? 5

28. (a) List the sequence of events in the uterus of a human female from
fertilisation of egg till childbirth.

(b) State the changes that are observed in the uterus if fertilisation of
egg does not occur. 5
OR
(a) What is vegetative propagation ? List three of its advantages.
Name two methods employed to grow new plants through
vegetative propagation.

(b) Explain, giving reason, why more complex organisms cannot give
rise to new individuals through regeneration. 5

29. (a) Why is nutrition necessary for the human body ?

(b) What causes movement of food inside the alimentary canal ?

(c) Why is small intestine in herbivores longer than in carnivores ?

(d) What will happen if mucus is not secreted by the gastric glands ? 5

.31/4/3 21 P.T.O.

30. {H$gr Eogo n[anW H$m ì`dñWm AmaoI It{ME {Og_| 2 V Ho$ VrZ gobm| H$s ~¡Q>ar, nmíd© _|
g§`mo{OV 10 , 20  VWm 30  Ho$ VrZ à{VamoYH$m| H$m g§`moOZ, EH$ ßbJ Hww§$Or VWm EH$
Eo_rQ>a, g^r loUr _| g§`mo{OV h¢ & Bg n[anW H$m Cn`moJ H$aHo$ {ZåZ{b{IV H$m _mZ kmV
H$s{OE :
(a) àË`oH$ à{VamoYH$ go àdm{hV Ymam
(b) n[anW _| àdm{hV Hw$b Ymam
(c) n[anW H$m Hw$b à^mdr à{VamoY 5

AWdm
{H$gr 6 V H$s ~¡Q>ar go Xmo gd©g_ à{VamoYH$, {OZ_| àË`oH$ H$m à{VamoY 15  h¡,
~mar-~mar go nhbo (i) loUr _|, Am¡a {\$a (ii) nmíd© _| g§`mo{OV {H$E JE h¢ & àË`oH$ àH$aU
_| à{VamoYH$m| Ho$ g§`moOZ Ûmam Cn^wº$ e{º$ Ho$ AZwnmV H$m n[aH$bZ H$s{OE & 5

.31/4/3 22

30. Draw a schematic diagram of a circuit consisting of a battery of 3 cells of
2 V each, a combination of three resistors of 10 , 20  and 30 
connected in parallel, a plug key and an ammeter, all connected in series.
Use this circuit to find the value of the following :

(a) Current through each resistor

(b) Total current in the circuit

(c) Total effective resistance of the circuit 5

OR

Two identical resistors, each of resistance 15 , are connected in
(i) series, and (ii) parallel, in turn to a battery of 6 V. Calculate the ratio
of the power consumed in the combination of resistors in each case. 5

.31/4/3 23 P.T.O.