PRACTICE PAPER - 2

CLASS : X SUBJECT: SCIENCE

M.M.: 80 DURATION: 3 HRS

GENERAL INSTRUCTIONS:
i) All questions are compulsory.
ii) The question paper has five sections and 39 questions. All questions are compulsory.
iii) Section–A has 16 MCQs and 4 assertion-reason type of 1 mark each; Section–B has 6 questions of
2 marks each; and Section–C has 7 questions of 3 marks each; Section–D has 3 questions of 5 marks
each; Section–E has 3 case based question of 4 marks.
iv) Internal choices have been provided in some questions. A student has to attempt only one of the
alternatives in such questions.
v) For case study questions in section E, there is one choice in one subpart, with 3 questions based per
case study.
SECTION A (MCQs)

Q1 Choose the event that does not occur in photosynthesis 1M

(a) Absorption of light energy by chlorophyll
(b) Oxidation of carbon to carbon dioxide
(c) Reduction of carbon dioxide to carbohydrates
(d) Conversion of light energy to chemical energy

Q2 Electrical impulse travels in a neuron from 1M

(a) Dendrite → axon → axonal end → cell body
(b) Cell body → dendrite → axon → axonal end
(c) Dendrite → cell body → axon → axonal end
(d) Axonal end → axon → cell body → dendrite

Q3 In which of the following groups of organisms, food materials are broken down outside the 1M
body and absorbed?
(a) Mushroom, green plants, Amoeba (b) Yeast, mushroom, bread mould
(c) Paramecium, Amoeba, Cuscuta (d) Cuscuta, lice, tapeworm

Q4 Posture and balance of human body is controlled by 1M

(a) cerebrum (b) cerebellum (c) medulla oblongata (d) pons

Q5 What prevents the backflow of blood inside the heart during contraction? 1M
(a)Thick muscular walls of ventricles (b) Thin walls of atria
(c)Valves in heart (d) All of the above

Q6 A student took solid quicklime in a China dish and added a small amount of water. He heard 1M
(a) a popping sound (b) a crackling sound
(c) a hissing sound (d) no sound at all

Q7 When hydrogen sulphide gas is passed through a blue solution of copper sulphate, a black 1M
 precipitate of copper sulphide is obtained and the sulphuric acid so formed remains in the
solution. The reaction is an example of-
(a) a combination reaction (b) a displacement reaction
(c) a decomposition reaction (d) a double displacement reaction

Q8 A reddish brown coloured metal used in electric wires, when powdered and heated strongly 1M
in an open China dish, its colour turns black. When hydrogen gas is passed over this black
substances, it regains its original colour. Based on this information, the metal and black
coloured substances are
(a) copper and copper nitrate (b) silver and silver oxide
(c) copper and copper oxide (d) aluminium and aluminium oxide

Q9 The diagram shows the pH values of four solutions. 1M

Which of these solutions are alkaline?

(a) P only (b) P and Q only (c) Q, R and S only (d) R and S only

Q10 Substance K reacts with sodium carbonate to form a gas. The gas turns limewater cloudy. 1M
What is substance K and which process takes place in the reaction?

K PROCESS

A ETHANOL COMBINATION

B ETHANOL NEUTRALISATION

C HYDROCHLORIC ACID COMBUSTION

D HYDROCHLORIC ACID NEUTRALISATION

i. A ii. B iii. C iv. D

Q11 A gas is escaping from a pipe in a chemical plant. A chemist tests this gas and finds that it is 1M
alkaline. What is this gas?

a) ammonia b) chlorine c) hydrogen d) sulphur dioxide

Q12 Which of the following is a characteristic of metals? 1M

(a) They have one to three valence electrons (b) They have 4 to 8 valence electrons

(c) They are brittle (d) They are capable to form anions easily

Q13 Power of the lens is -4D, its focal length is 1M

 (a) 4m (b) -40m (c) -0.25m (d) . -25m

Q14 The optical phenomena, twinkling of stars, is due to 1M

(a) Atmospheric reflection (b) Total internal reflection
(c) Atmospheric refraction (d) Total refraction

Q15 A cell, a resistor, a key and ammeter are arranged as shown in following the circuit diagrams. 1M

Which circuit shows the correct position of ammeter in the circuit?

(a) Circuit (i) (b) circuit (ii)

(c) Circuit (iii) (d) All the circuits are correct

Q16 What is the correct order of the phenomenon involved in the formation of a rainbow? 1M
(a) Reflection, refraction and dispersion
(b) Refraction, dispersion and internal reflection
(c) Refraction, scattering and internal reflection
(d) Dispersion, scattering and internal reflection

Q17 to Q20 are assertion-reasoning based questions.

These consist of two statements - Assertion (A) and Reason (R). Answer these questions
selecting the appropriate options given below:
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.

Q17 Assertion (A): The mirrors used in search lights are concave spherical. 1M
Reason (R): In a concave spherical mirror the image formed is always virtual.
Q18 Assertion (A): It is not possible to see a virtual image by eye. 1M

Reason (R): The rays that seem to emanate from a virtual image do not in fact emanate from
the image.

Q19 ASSERTION: Fresh milk in which baking soda is added takes longer time to set as curd 1M
REASON: Baking soda decreases the pH value of fresh milk to below 6.
Q20 Assertion: Insulin regulates blood sugar level. 1M
Reason: Insufficient secretion of insulin will cause diabetes.

SECTION B
Q21 to 26 are very short answer questions

Q21 2M

Label the parts of a neuron in the above given figure.

Q22 a) Why is blood circulation in the human heart called double circulation? 2M
b) What is the advantage of having a four chambered heart?

Q23 2M

a) What does the above experimental set-up demonstrate?

b) Which type of tropism is exhibited by the plant shoot and plant root in the above
set-up?.

Q24 State reasons for the following: 2M

(a) A tarnished copper vessel begins to shine again rubbed with lemon.
(b) Why does the colour of ferrous sulphate change on heating?

Q25 The graph below represents the neutralisation reaction. The pH of the solution changes 2M
as we add excess of base to the acid.
 i. What happens to the concentration of H3O+ions when a solution of acid is
diluted?
ii. What happens to the concentration of OH- ions when excess of base is added to
a solution of sodium hydroxide?.
OR
Write name of the compound:
(a) Used for softening hard water.
(b) Used as an antacid.
(c) Which is a component of washing soda.
(d) Which is used as an oxidizing agent in many chemical industries?

Q26 If the speed of light in vacuum is 3 x 108 ms-1, find the speed of light in a medium of absolute 2M
refractive index 1.5.
OR

A transparent medium A floats on another transparent medium B. When a ray of light travels
obliquely from medium A to B, the refracted ray bends away from the normal. Which of these
two media is optically denser and why?

SECTION C
Q27 to Q33 are short answer questions
Q27 (a) Define the SI unit of potential difference. 3M
(b) What are mA and µA ? How are they related to ampere(A) ?
(c) A charge of 20 C passes through a wire which is maintained at a potential difference of 5
V. Calculate the amount of work in moving the charge across the wire?

Q28 The image of a candle flame formed by a lens is obtained on a screen placed on the other side 3M
of the lens. If the image is three times the size of the flame and the distance between lens and
image is 80 cm, at what distance should the candle be placed from the lens? What is the nature
of the image and the focal length of the lens?
Q29 A convex lens of focal length 20 cm can produce a magnified virtual image. Is this a correct 3M
statement? If yes, then specify the position of the object and draw a ray diagram to support
your answer.
OR
An object 5 cm in length is placed 20 cm in front of a convex mirror of radius of curvature 30
cm. Find the position, nature and size of the image formed.

Q30 Describe how washing soda is prepared from sodium chloride. 3M

Give one use of washing soda.

Q31 Identify the following: 3M

a. most ductile metal b. liquid non metal
c. best conducting metal d. lustrous non metal
e. metal with low melting point f. soft metal.

Q32 Give reasons:- 3M

a) Leaves of plants help in excretion.
b) Rate of breathing is much faster in aquatic organisms than that in terrestrial organisms.
c) Small intestine in herbivores is longer than in carnivores.

Q33 Mention the glands that secrete the following hormones and write one function of each 3M
hormone
a) Adrenaline
b) Testosterone
c) Growth hormone
OR
a) How does control and coordination takes place in plants?
b) Name any two phytohormones and write one function of each.

SECTION D
Q34 TO Q36 are long answer questions

Q34 a) What is the functional unit of kidney? 5M

b) Name the major processes involved in the formation of urine.
c) Draw a neat diagram of a human excretory system and label the following:
i) long tube which collects urine from kidney
ii) store urine temporarily
iii) produce urine
OR

a) What is the role of acid in our stomach?

b) How is the small intestine designed to absorb digested food?
c) Draw a neat diagram of human digestive system and label the following organs:
i) food is completely digested here
 ii) absorbs water and minerals
iii) produces bile juice

Q35 a. What is observed when carbon dioxide gas is passed through lime water. 5M
(i) For a short duration
(ii) For a long duration?
Also, write the chemical equations for the reaction involved.
b. Why do we store silver chloride in dark coloured bottles?
c. Blue Copper Nitrate crystals turns black when heated.
OR
A. What type of chemical reactions take place when:
(a)Limestone is heated?
(b)A magnesium wire is burnt in air?
(c)Electricity is passed through water?
(d)Ammonia and hydrogen chloride are mixed?
(e)Silver bromide is exposed to sunlight?
B. A powdered salt X was taken in a dry test tube and heated. Brown fumes of nitrogen
dioxide and a yellow residue of lead oxide were formed. Identify the salt X by giving
its chemical formula.
Write a balanced chemical equation for the reaction.

Q36 Explain the refraction of light through a triangular glass prism using a labelled ray diagram. 5M
Mark the following in the diagram:
A – Angle of prism, D – Angle of deviation, i – Incident angle

r – Angle of refraction, e – Emergent angle

Also label the Incident, Refracted and the Emergent rays

Define the angle of deviation.

SECTION E
Q37 to Q39 are case-based / data-based questions with 2 to 3 short sub-parts.
Internal choice is provided in one of these sub-parts

Q37 There are mainly three common refractive defects of vision These are 4M
(i) Myopia or near-sightedness
(ii) Hypermetropia or far – sightedness
(iii) Presbyopia.
Myopia is also known as near-sightedness. A person with myopia can see nearby objects
clearly but cannot see distant objects distinctly. A person with this defect has the far point
nearer than infinity. Such a person may see clearly up to a distance of
a few metres.
 Hypermetropia is also known as far -sightedness. A person with hypermetropia can see distant
objects clearly but cannot see nearby objects distinctly.

(a) Identify the defect of vision shown in the diagram. (1)

(b) How can this defect be corrected? (1)
(c) State 2 causes of Presbyopia. (2)
OR
(c) Identify the parts A, B, C and D in the diagram of the human eye provided below.(2)

Q38 The common salt is an important raw material for various materials of daily use, such as 4M
sodium hydroxide, baking soda, washing soda, bleaching powder and many more. When
electricity is passed through an aqueous solution of sodium chloride called brine, it
decomposes to form sodium hydroxide. The process is called the chlor-alkali process because
of the products formed .
i. Identify gas A, gas B and the solution C
ii. Which raw material is being used in this process?
iii. Where is gas A and solution C obtained in the electrolytic cell?
iv. Write a balanced chemical equation for the reaction taking place.
OR
iv. Specify the states of reactants and products in the equation for the reaction.

Q39 Human nervous system comprises central nervous system and peripheral nervous system. The 4M
former is hollow and is covered externally by skeleton and latter connects CNS with different
parts of the body. It has voluntary and involuntary components. Each part of nervous system
has specific functions.

i) Name two types of nerves of peripheral nervous system.

ii) Where are olfactoreceptors located in the human brain? What is their function?.
iii) Name the largest part of human brain. Write one function of it.
OR
Which bony structure enclose and protect the human brain and spinal cord?