Goa Board Class 10 Question Paper June 2019 Science English

2019 VI 21 0230 Seat No.

Time : 2½ Hours SCIENCE (E)

Subject Code

S 0 3 1

Total No. of Questions : 5 (Printed Pages : 15) Maximum Marks : 65

INSTRUCTIONS : (i) The question paper comprises of five questions of 13

marks each.

(ii) All questions are compulsory.

(iii) There is no overall choice, however internal choice has

been provided in two questions of three marks and two

questions of four marks category. You have to attempt

only one option in such questions.

(iv) Begin each question on a fresh page.

(v) Figures to the right indicate full marks.

1. (A) (i) Select the most correct alternative from those given below each

statement and write the completed statement : 1

(a) The thinking part of the brain is the .................

• Hindbrain

• Forebrain

• Midbrain

• Spinal Cord

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(b) The movement of the roots of a plant towards the water

is termed ...................

• Hydrotropism

• Chemotropism

• Phototropism

• Geotropism

(ii) Give one term for the following : 1

(a) The gap between two neurons.

(b) Receptors responsible for taste.

(iii) The thinking process of animals is not fast enough. How do

animals manage to react to a stimulus ? 1

(iv) Hari had a problem with carbohydrate, protein and fat

metabolism in his body : 1

(a) Name the element he must include in his diet to

overcome this problem.

(b) Give one symptom of the deficiency disease caused in the

above.

(B) (i) Answer the following : 2

(a) Why are highly reactive metals such as Aluminium used

as reducing agents ?

(b) MgCl2 does not conduct electricity in the solid state. Give

reasons.

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(ii) Answer the following : 2

(a) Name :

(1) Water harvesting structures in Karnataka.

(2) The movement to protect trees in the Himalayas.

(b) The forest department has converted vast tracts of forests

into monocultures. What are the disadvantages of this

procedure ?

(iii) Attempt the following : 2

(a) The metal sodium is kept immersed in Kerosene oil in

the school laboratory. Why is it not kept in the open ?

(b) Solder is an alloy of lead and tin :

(1) Give one property of solder.

(2) State and important use of solder.

(C) Attempt the following : 3

(i) Construct a Food Chain with the help of the organisms given

below :

Hawk, Grass, Snake, Hen.

(ii) Why is it not advisable to have a six step food chain ?

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(iii) If Pesticides enter the above food chain.

(a) In which organism will it be found in the maximum

amount ?

(b) What is this phenomenon called ?

2. (A) (i) Select the most correct alternative from those given below each

statement and write the completed statement : 1

(a) Electrolysis of water is an example of a ............... reaction.

• Combination

• Double displacement

• Decomposition

• Displacement

(b) Decomposition of Lead Nitrate produces .............. gases.

• O2 and CO2

• O2 and NO2

• NO2 and NO3

• NO and NO2

(ii) State : 1

(a) The difference between the number of water molecules

in Gypsum and Plaster of Paris.

(b) The compound found in tooth enamel.

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(iii) An indicator is added to Potassium Hydroxide and the solution

turns pink : 1

(a) Name the indicator that is added.

(b) What is the colour change you will observe if you add

Litmus to the same solution ?

(iv) Baking soda is used to make cakes light and fluffy. Give any

two other uses of Baking soda. 1

(v) Four solutions A, B, C and D have pH of 2, 6, 7 and 13

respectively : 1

(a) Which of the above solutions is a strong acid ?

(b) Which solution will have the highest number of

Hydronium ions ?

(B) (i) Answer the following : 2

(a) In the chemical reaction given below :

ZnO + C Zn + CO

(1) Identify the Oxidising agent

(2) Name the substance which is reduced.

(b) Two chemicals mixed by the laboratory assistant in the

laboratory are Barium chloride and Potassium Sulphate.

Write a balanced Chemical Equation for the above

reaction.

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(ii) Answer the following : 2

(a) Differentiate between Translocation and transpiration.

(b) A rabbit has a longer small intestine than a tiger. Give

scientific reason.

(C) Attempt the following : 4

(i) Glucose is broken down into a three carbon compound during

Respiration. Name :

(a) The three carbon compound

(b) The type of respiration in which CO2 and Ethanol are

the end products.

(ii) Why are the gills of Fish fine and delicate ?

(iii) The human heart is the pump of the body.

(a) From which chamber is the oxygenated blood pumped to

all parts of the body ?

(b) Name the blood vessel in the heart which carries blood

to the lungs.

(iv) What does the term double circulation mean ?

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OR

(C) Attempt the following : 4

(i) Food is broken down in the alimentary canal into smaller

molecules :

(a) What is the importance of HCl in the stomach of man ?

(b) What is the role of Bile Salts in the Emulsification of

Fats ?

(ii) Excretion of Nitrogenous wastes is carried out by the Kidneys.

Name :

(a) The opening through which the urine is released.

(b) The basic filtration units in the kidney.

(iii) State two factors on which the amount of water reabsorbed in

the kidney depends on.

3. (A) (i) Observe the correlation in the first pair and complete the second

pair : 1

(a) CH3OH : Methanol : : CH3CH2COOH : ...............

(b) Saturated hydrocarbons : substitution reactions : :

Unsaturated hydrocarbons : ..........

(ii) A housewife notices that the cooking vessels she uses are

getting blackened. What can she do to prevent this from

happening ? 1

(iii) What do you understand by Cross Pollination ? 1

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(B) (i) Chlorine, Bromine and Iodine form a Dobereiners Triad. If the

approximate atomic mass of Chlorine is 35 and that of iodine

is 127 : 2

(a) Find the atomic mass of Bromine.

(b) Give any two limitations of Mendeleev’s periodic

classification.

(ii) Answer the following : 2

(a) Give a chemical equation for the reaction of Ethanol with

excess hot conc. Sulphuric acid.

(b) Draw the structural formula of Butanone.

(iii) Four elements W, X, Y and Z have atomic numbers 12, 18,

4 and 16 : 2

(a) Which of the above will form an acidic oxide ?

(b) Which element represents an inert gas ?

(c) Which element belongs to the second period ?

(d) Which element will be larger in size W or Z ?

(C) Attempt the following : 4

(i) Draw a neat scientific diagram of the Female Reprdouctive

System and label :

(a) Vagina and

(b) Oviduct.

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(ii) Write two changes that occur in teenage boys during the period

of Adolescence.

(iii) Tying of the Fallopian tubes is a method of Contraception. How

does this method prevent pregnancy ?

OR

(C) Attempt the following : 4

(i) Draw a neat scientific diagram showing budding in Hydra (two

stages) and label . Bud. Tentacles.

(ii) Name the following :

(a) An organism that reprdouces by Fragmentation.

(b) The types of asexual reproduction seen in Planaria.

(iii) If the copying of DNA during sexual reproduction is not

accurate, what will be the consequences ?

4. (A) (i) Select the correct alternative from those given below each

statement and write the completed statement : 1

(a) The power of a convex lens is +4D, then its focal length

will be ................

• 0.40 m

• 400 cm

• 0.25 m

• 250 cm

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(b) In a Solar Furnace, sunlight is concentrated at the

.................. of the Concave mirror.

• Centre of Curvature

• Optical Centre

• Pole

• Focus

(ii) Answer the following : 1

(a) A ray of light travelling in air enters obliquely into a

glass slab. Does the ray move towards the normal or away

from it ?

(b) Name the law represented by the formula :

n = sin i/Sin r.

(iii) Vimal combs her hair is front of a plane mirror. Write two

characteristics of her image. 1

(iv) What is the condition necessary for Ocean Thermal power plants

to operate ? 1

(B) (i) The fossil of a Dinosaur was found only a few years ago in the

Narmada valley : 2

(a) What is a fossil ?

(b) Give two ways by which you can find the age of a

fossil.

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(ii) Biogas plants are considered to be a boon to the farmers. 2

(a) Why is Biogas said to be an excellent fuel ?

(b) Name the two elements present in the slurry which is

used as a manure.

(iii) Answer the following : 2

(a) Name :

(i) The sex chromosome boys inherit from their father.

(ii) Organs having different structures but performing

the same function.

(b) Gauri hurts her hand in an accident and two fingers

had to be cut off. Her child is born with all the fingers

on his hand. What conclusion can you draw from

this ?

(C) Attempt the following : 3

(i) Draw a Ray diagram to show the formation of an image when

the object is placed between the pole and the focus of a Concave

Mirror.

(ii) If the Magnification produced by a Convex Lens is –1.5, what

would be the position and nature of the image.

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OR

Answer the following : 3

(i) Draw Ray diagram to show the formation of an image when

the object is placed between F 1 and 2F 1 of a convex

lens.

(ii) An object is placed at a distance of 15 cm in front of a Concave

Mirror. If an image of its is formed at 30 cm from the mirror,

find the focal length of the mirror.

5. (A) (i) Select the most correct alternative given below each statement

and write the completed statement : 1

(a) An appliance like an elecric iron takes a current from

circuit rated ............

• 15 A

• 220 A

• 110 A

• 5 A

(b) An electric fuse is used to .............

• Increase the current flowing through a circuit

• Allow the connection of many appliances in a socket

• Provide a low resistance conducting path for current

• Stop the flow of unduly high electric current

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(ii) Match the items in Column A with items in Column B and

write the corrected pairs : 1

Column A Column B

(a) Right Hand Thumb • Direction of induced

Rule current

(b) Flemings Right hand • Direction of force

rule produced due to magnetic

field

• Direction of magnetic

field in a straight

conductor

(iii) When Mars is viewed through a telescope it does not appear to

twinkle. Comment. 1

(iv) Soham uses a 600 W Music System for 5 hours daily. Calculate

the electrical energy consumed in kWH for 30 days. 1

(B) Answer the following : 2

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(a) Observe closely the above diagram and answer the following

questions :

(1) Name the instrument used to detect current.

(2) Name the process by which change in magnetic field in

Coil A produces a current in Coil B.

(b) Kunal draws magnetic field lines close to the axis of a current

carrying circular loop. As he moves away, towards the centre

of the circular loop, he observes that the lines keep on diverging.

How will you explain his observation ?

(C) Amey can read printed matter on sign boards on the roadside but

cannot read his textbook well : 3

(i) Name the eye defect he is suffering from.

(ii) Which lens can be used to correct this defect ?

(iii) Give two cuases of this defect.

(iv) How is the near point of the eye affected by this defect ?

OR

(C) Mr. Sudhakar a 60 year old man, visits the eye doctor because he

cannot see clearly. The doctor finds that his eye lens is cloudy : 3

(i) Name the eye defect he is suffering from.

(ii) How can he regain his vision ?

(iii) Why do some people require Bi-focal lenses ?

(iv) The Power of Accommodation usually decreases in elderly

people. Give two reasons for the same.

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(D) Answer the following : 4

(i) Draw a neat circuit diagram as described below :

Connect three Resistors R1, R2 and R3 in Parallel, connect

them with a battery, ammeter and a plug key, insert a voltmeter

across the resistors. Show the direction of the flow of current.

(ii) In the circuit diagram given below, find :

(a) The total resistance in the circuit.

(b) The total current flowing in the circuit.

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