“The Knowledge Library”

Knowledge for All, without Barriers…

An Initiative by: Kausik Chakraborty.

“The Knowledge Library”

Knowledge for All, without Barriers……….
An Initiative by: Kausik Chakraborty.

The Knowledge Library

CBSE Science MCQ for Class 10

Q. Give the ratio in which hydrogen and oxygen are present in water by volume.

(a) 1:2

(b) 1:1

(c) 2:1

(d) 1:8

Correct Answer: (c) 2:1

Q. One of the following processes does not involve a chemical reaction, that is:

(a) Melting of candle wax when heated

(b) Burning of candle wax when heated

(c) Digestion of food in your stomach

(d) Ripening of banana

Correct Answer: (a) Melting of candle

Q. The chemical formula of magnesium oxide is ______.

(a) MgO2

(b) Mg2O

(c) MgO

(d) Mg(OH)2

Correct Answer: (c) MgO

Q. From the following, which one is an example of a chemical reaction?

(a) Grapes get fermented

(b) Breakdown of food

(c) Formation of curd

(d) All of the above

Correct Answer: (d) All of the above

Q. Which of the following reactions is used in black-and-white photography?

(a) Combination Reaction

(b) Decomposition Reaction

(c) Displacement reaction

(d) Oxidation reaction

Correct Answer: (b) Decomposition Reaction

Q. Which of the following shows an oxidation reaction?

(a) Gain of oxygen

(b) Loss of oxygen

(c) Gain of hydrogen

(d) None of the above

Answer: (a) Gain of oxygen

Q. Which Acid is present in Tomato?

(A) Citric Acid

(B) Oxalic Acid

(C) Lactic Acid

(D) HCl

Correct Answer: (B) Oxalic Acid

Q. pH value less than 7 indicates that the solution is –

(A) Acidic

(B) Basic

(C) Neutral

(D) No effect

Correct Answer: (A) Acidic

Q5. Which of the following is neutral salt?

(A) NH4Cl




Correct Answer: (B) CH3COONH4

Q. Lactic Acid is present in –

(A) Orange

(B) Tea

(C) Curd

(D) Vinegar

Correct Answer: (C) Curd

Q. Farmers neutralise the effect of Acidity on the soil by adding –

(A) Slaked lime

(B) Gypsum

(C) Caustic soda

(D) Baking soda

Correct Answer: (A) Slaked lime

Q. Which of the following are present in a dilute Aqueous solution of hydrochloric acid?

(A) H3O + Cl–

(B) H3O + OH–

(C) Cl– + OH–

(D) Unionised HCl

Correct Answer: (A) H3O + Cl–

Q. CuSO4.5H2O: In this Compound, the water molecule is called –

(A) Pure water

(B) Water of crystallisation

(C) Soda water

(D) None of these

Correct Answer: (B) Water of crystallisation

Q. Which of the following salts does not contain water of crystallisation?

(A) Blue vitriol

(B) Baking soda

(C) Washing soda

(D) Gypsum

Correct Answer: (B) Baking soda

Q. An aqueous solution turns the red litmus solution blue. Excess addition of which of the following solutions would reverse the change?

(A) Baking powder

(B) Lime

(C) Ammonium hydroxide solution

(D) Hydrochloric acid

Correct Answer: (D) Hydrochloric acid

Q. In which pH range does our body work to survive in the atmosphere?

(A) 5.5 to 8.5

(B) 7.0 to 7.8

(C) 2.3 to 7.0

(D) 7.5 to 12.5

Correct Answer: (B) 7.0 to 7.8

Q. What is the chemical formula of POP (Plaster of Paris)?

(A) CaSO4.2H2O

(B) CaSO4.3H2O

(C) CaSO4.1/2H2O

(D) CaCO3.1/2H2

Correct Answer: (C) CaSO4.1/2H2O

Q. Which salt is acidic in nature?

(A) NH4Cl


(C) NaCl


Correct Answer: (A) NH4Cl

Q. At what temperature is gypsum heated to form Plaster of Paris?

(A) 35°C

(B) 70°C

(C) 80°C

(D) 100°C

Correct Answer: (D) 100°C

Q. Sodium carbonate reacts with hydrochloric acid and produces –

(A) NaCl

(B) CO2

(C) H2O

(D) All of the above

Correct Answer: (D) All of the above

Q. Which acid is present in tamarind?

(A) Tartaric acid

(B) Oxalic Acid

(C) Lactic Acid

(D) Citric Acid

Correct Answer: (A) Tartaric acid

Q. Which of the following oxides of iron would be obtained on the prolonged reaction of iron with steam?

a) FeO

b) Fe2O3

c) Fe3O4

d) Fe2O3 and Fe3O4

Correct Answer: (c) Fe3O4

Q. A non-metal used to preserve food material is:

a) Carbon

b) Phosphorus

c) Sulphur

d) Nitrogen

Correct Answer: (d) Nitrogen

Q. The metals that float when treated with water are:

a) Manganese and sodium

b) Sodium and calcium

c) Magnesium and sodium

d) Magnesium and calcium

Correct Answer: (d) Magnesium and calcium

Q. What happens when a pellet of sodium is dropped in water?

(a) It catches fire and forms oxide

(b) It absorbs heat and forms oxide

(c) It catches fire and forms hydroxide

(d) It absorbs heat and forms hydroxide

Correct Answer: (c) It catches fire and forms hydroxide

Q. When calcium oxide is added to water, it completely dissolves in water without forming bubbles. What products are formed in this reaction?

(a) Ca and H2

(b) Ca and H2O2

(c) Ca(OH)2

(d) CaH2

Correct Answer: (c) Ca(OH)2

Q. Which of the following can undergo a chemical reaction?

a) MgSO4 + Fe

b) ZnSO4 + Fe

c) MgSO4 + Pb

d) CuSO4 + Fe

Correct Answer: (d) CuSO4 + Fe

Q. When a non-metal is allowed to react with water:

a) CO2 gas is formed

b) H2 gas is formed

c) Product formed depends on the temperature

d) No products are formed

Correct Answer: (d) No products are formed

Q. Aqua regia is a freshly prepared mixture of concentrated HNO3 and concentrated HCl in the ratio of:

a) 1:3, respectively

b) 2:3, respectively

c) 3:1, respectively

d) 3:2, respectively

Correct Answer: (a) 1:3, respectively

Q. The electronic configuration of an element is found to be 2, 4. How many bonds can one carbon atom form in a compound?

(a) 1

(b) 2

(c) 4

(d) 6

Correct Answer: (c) 4

Q. A carbon compound contains two atoms of carbon. Which name should the carbon compound bear?

(a) Butane

(b) Ethane

(c) Methane

(d) Propane

Correct Answer: (b) Ethane

Q. Which of the following is the molecular formula of cyclobutane?

a) C4H10

b) C4H6

c) C4H8

d) C4H4

Correct Answer: (c) C4H8

Q. Which of the following belongs to a homologous series of alkynes?

(a) C6H6

(b) C2H6

(c) C2H4

(d) C3H4

Correct Answer: (d) C3H4

Q. How many single bonds are present in methane?

(a) Four

(b) Five

(c) Six

(d) Three

Correct Answer: (a) Four

Q. A hydrocarbon should have a minimum of ______ carbon atoms to show isomerism.

(a) Three

(b) Four

(c) Fived

(d) Six

Correct Answer: (b) Four

Q. Which of the following forms the basis of the modern periodic table?

a) Atomic mass

b) Atomic number

c) Number of nucleons

d) All of the above

Correct Answer: (b) Atomic number

Q. Which of the following is the most reactive element of group 17?

a) Oxygen

b) Sodium

c) Fluorine

d) Magnesium

Correct Answer: (c) Fluorine

Q. Which of the following is the correct order of the atomic radii of the elements oxygen, fluorine and nitrogen?

a) O < F < N

b) N < F < O

c) O < N < F


Correct Answer: (d) F < O < N

Q. What happens to the electropositive character of elements on moving from left to right in a periodic table?

a) Increase

b) Decreases


d) First decreases, then increases

Correct Answer: (b) First increases, then decreases

Q. What is the other name for group 18th elements?

a) Noble gases

b) Alkali metals

c) Alkali earth metals

d) Halogens

Correct Answer: (a) Noble gases

Q. Which group elements are called transition metals?

a) Group number 1 to 2

b) Group number 13 to 18

c) Group number 3 to 12

d) Group number 1 to 8

Correct Answer: (c) Group number 3 to 12

Q. The electronic configuration of an element M is 2, 8, 4. In the modern periodic table, the element M is placed in

a) 4th group

b) 2nd group

c) 14th group

d) 18th group

Correct Answer: (c) 14th group

Q. Which of the following elements has 2 shells, and both are completely filled?

a) Helium

b) Neon

c) Calcium

d) Boron

Correct Answer: (b) Neon

Q. Boron is a non-metal and is placed under group 13 and period 2. How can boron form bonds with other elements?

(a) By sharing 5 electrons

(b) By sharing 3 electrons

(c) By sharing 2 electrons

(d) By sharing 1 electron

Correct Answer: (b) By sharing 3 electrons

Q. In amoeba, food is digested in the:

(a) Food vacuole

(b) Mitochondria

(c) Pseudopodia

(d) Chloroplast

Correct Answer: (a) Food vacuole

Q. In which of the following groups of organisms are food materials broken down outside the body and absorbed?

(a) Mushroom, green plants, amoeba

(b) Yeast, mushroom, bread mould

(c) Paramecium, amoeba, cuscuta

(d) Cuscuta, lice, tapeworm

Correct Answer: (b) Yeast, mushroom, bread mould

Q The contraction and expansion movement of the walls of the food pipe is called:

(a) Translocation

(b) Transpiration

(c) Peristaltic movement

(d) Digestion

Correct Answer: (c) Peristaltic movement

Q. What are the products obtained by anaerobic respiration in plants?

(a) Lactic acid + energy

(b) Carbon dioxide + water + energy

(c) Ethanol + carbon dioxide + energy

(d) Pyruvate

Correct Answer: (c) Ethanol + carbon dioxide + energy

Q. The respiratory pigment in human beings is:

(a) Carotene

(b) Chlorophyll

(c) Haemoglobin

(d) Mitochondria

Correct Answer: (c) Haemoglobin

Q. The opening and closing of the stomatal pore depend upon:

(a) Oxygen

(b) Temperature

(c) Water in the guard cells

(d) Concentration of CO2

Correct Answer: (c) Water in the guard cells

Q. Chemicals present in tobacco smoke lead to the breakdown of the elastic tissue in the alveoli. Name this specific condition.

(a) Heart disease

(b) Emphysema

(c) Bronchitis

(d) Lung cancer

Correct Answer: (b) Emphysema

Q. What is the percentage of oxygen in the expired air when a person is resting?

(a) 12%

(b) 16%

(c) 20%

(d) 24%

Correct Answer: (b) 16%

Q. Which parts of the brain control blood pressure?

(a) Spinal cord, skull, hypothalamus

(b) Cord, skull, cerebrum

(c) Pons, medulla, cerebellum

(d) Pons, medulla, pituitary

Correct Answer: (c) Pons, medulla, cerebellum

Q. Fruits are formed from the

a) Stamen

b) Stigma

c) Ovary

d) Ovule

Correct Answer: (c) Ovary

Q. The male reproductive parts of a flower, the stamens, are collectively known as

a) Androecium

b) Filament

c) Anther

d) Gynoecium

Correct Answer: (a) Androecium

Q. Which of the following diseases is transmitted sexually?

a) Kala Azar

b) Jaundice

c) Cholera

d) Syphilis

Correct Answer: (d) Syphilis

Q. AIDS is a deadly disease which is caused by

a) a protozoan

b) a fungus

c) a bacterium

d) a virus

Correct Answer: (d) a virus

Q. Which among the following diseases is not sexually transmitted?

a) Syphilis

b) Hepatitis


d) Gonorrhea

Correct Answer: (b) Hepatitis

Q. The ratio of the number of chromosomes in a human zygote and a human sperm is

a) 2:1

b) 3:1

c) 1:2

d) 1:3

Correct Answer: (a) 2:1

Q. A person went for a medical check-up and found that the curvature of his eye lens was increasing. Which defect is he likely to suffer from?

(a) Myopia

(b) Cataract

(c) Presbyopia

(d) Hypermetropia

Correct Answer: (a) Myopia

Q. When light rays enter the eye, most of the refraction occurs at the

(a) Crystalline lens

(b) The outer surface of the cornea

(c) Iris

(d) Pupil

Correct Answer: (b) The outer surface of the cornea

Q. In which part of the human eye is the image of an object formed?

(a) Iris

(b) Pupil

(c) Retina

(d) Cornea

Correct Answer: (c) Retina

Q. The splitting of white light into different colours on passing through a prism is called

(a) reflection

(b) refraction

(c) dispersion

(d) deviation

Correct Answer: (c) dispersion

Q. The deflection of light by minute particles and molecules of the atmosphere in all directions is called ____________ of light.

(a) dispersion

(b) scattering

(c) interference

(d) Tyndall effect

Correct Answer: (b) scattering

Q. When white light enters a glass prism from the air, the angle of deviation is least for

(a) blue light

(b) yellow light

(c) violet light

(d) red light

Correct Answer: (d) red light

Q. The least resistance obtained by using 2 Ω, 4 Ω, 1 Ω and 100 Ω is

(a) < 100 Ω

(b) < 4 Ω

(c) < 1 Ω

(d) > 2 Ω

Correct Answer: (c) < 1 Ω

Q. A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of

(a) More length

(b) Less radius

(c) Less length

(d) More radius

Correct Answer: (d) More radius

Q. Electrical resistivity of a given metallic wire depends upon

(a) Its length

(b) Its thickness

(c) Its shape

(d) Nature of the material

Correct Answer: (d) Nature of the material

Q. Unit of electric power may also be expressed as

(a) Volt-ampere

(b) Kilowatt-hour

(c) Watt second

(d) Joule second

Correct Answer: (b) Kilowatt-hour

Q. Which of the following represents voltage?

(a) Work done / Current × Time

(b) Work done × Charge

(c) Work done × Time / Current

(d) Work done × Charge × Time

Correct Answer: (a) Work done / Current × Time

Q. If n resistors each of resistance R are connected in parallel combination, then their equivalent resistance is

(a) R/n2

(b) n2/R

(c) n/R

(d) R/n

Correct Answer: (d) R/n

Q. Two resistors connected in series give an equivalent resistance of 10 Ω. When connected in parallel, give 2.4 Ω. Then the individual resistance is

(a) each of 5 Ω

(b) 6 Ω and 4 Ω

(c) 7 Ω and 4 Ω

(d) 8 Ω and 2 Ω

Correct Answer: (b) 6 Ω and 4 Ω

Q. Two bulbs are rated 40W, 220W and 60W, 220W. The ratio of their resistances will be

(a) 4:3

(b) 3:4

(c) 2:3

(d) 3:2

Correct Answer: (d) 3:2

Q. A coil in the heater consumes power P on passing current. If it is cut into halves and joined in parallel, it will consume power

(a) P

(b) P/2

(c) 2 P

(d) 4 P

Correct Answer: (d) 4 P

Q. The most suitable material for making the core of an electromagnet is:

a) Steel

b) Iron

c) Soft iron

d) Aluminium

Correct Answer: (c) Soft iron

Q. Which of the following is not attracted by a magnet?

(a) Steel

(b) Cobalt

(c) Brass

(d) Nickel

Correct Answer: (c) Brass

Q. The front face of a circular loop of a wire is the North Pole, the direction of current in this face of the loop will be:

a) Clockwise

b) Anticlockwise

c) Towards North

d) Towards South

Correct Answer: (b) Anticlockwise

Q. The magnetic field inside a long straight solenoid carrying current:

a) Is zero

b) Decrease as we move towards its end

c) Is the same at all points

d) Increase as we move towards its end

Correct Answer: (c) Is the same at all points

Q. The force on a current-carrying conductor when placed perpendicular in a uniform magnetic field.

a) F=BIL

b) F=B/IL

c) F=L/BI

d) F=I/BL

Correct Answer: (a) F=BIL

Q. A soft iron bar is introduced inside a current-carrying solenoid. The magnetic field inside a solenoid:

a) Decrease

b) Will increase

c) Will become zero

d) Will remain unaffected

Correct Answer: (b) Will increase

Q. A student wants to extract energy from fossil fuels. Which process would help him to extract the energy from fossil fuel?

(a) burning

(b) crystallisation

(c) condensation

(d) distillation

Correct Answer: (a) burning

Q. Why is biogas considered a ‘good’ source of energy?

(a) as it produces ashes

(b) as it produces methane

(c) as it burns without releasing smoke

(d) as it decomposes in the absence of oxygen

Correct Answer: (c) as it burns without releasing smoke

Q. Which of these sources should he use for cooking without production of smoke?

(a) coal

(b) electricity

(c) petroleum

(d) wood

Correct Answer: (b) electricity

Q. The amount of energy that flows from one trophic level to another in a food chain is

a) 5%

b) 10 %

c) 20 %

d) 15 %

Correct Answer: (b) 10 %

Q. The primary consumers are

a) Carnivores

b) Herbivores

c) Omnivores

d) Producers

Correct Answer: (b) Herbivores

Q. Which of the following is responsible for the depletion of the ozone layer

a) CFCs

b) Oxygen

c) SO2

d) CO2

Correct Answer: (a) CFCs

Q. The driving force of any ecosystem is

a) Carbohydrates

b) Solar energy

c) Biomass

d) ATP

Correct Answer: (b) Solar energy

Q. Kitchen wastes can be hygienically disposed of through

a) Dumping

b) Composting

c) Incineration

d) Recycling

Correct Answer: (b) Composting

Q. Environment includes

a) Land, air, water

b) Light, temperature, rainfall

c) Plants, animals, microbes

d) All of these

Correct Answer: (d) All of these

Q. Which of the following is a linear arrangement of organisms?

a) Food chain

b) Food web

c) Trophic levels

d) Community

Correct Answer: (a) Food chain

Q. An agricultural cropland is

a) A biome

b) A natural ecosystem

c) An artificial ecosystem

d) None of these

Correct Answer: (c) An artificial ecosystem

Q. Problem of solid waste disposal can be reduced through

a) Recycling

b) Lesser pollution

c) More timber

d) Population control

Correct Answer: (a) Recycling

Q. An environment-friendly practice is

a) Using CFLs at homes and offices

b) Using the car to go to nearby places

c) Using AC in every room

d) Burning plastics

Correct Answer: (a) Using CFLs at homes and offices

Q. Which of the following limits the number of trophic levels in a food chain?

a) Water

b) Polluted air and water

c) Deficient food supply

d) Decrease in energy at higher trophic levels

Correct Answer: (d) Decrease in energy at higher trophic levels

Q. The cleaners of nature are

a) Producers

b) Consumers

c) Herbivores

d) Decomposers

Correct Answer: (d) Decomposers

Q. Ozone hole may cause

a) Mutations

b) Global warming

c) Skin cancer

d) All of these

Correct Answer: (d) All of these

Q. In a food chain, the third trophic level is always occupied by

a) Carnivores

b) Herbivores

c) Producers

d) Decomposers

Correct Answer: (a) Carnivores

Q. The biotic components of an ecosystem consist of

a) Plants and animals

b) Algae and fungi

c) Producers, consumers & decomposers

d) Air, water, soil

Correct Answer: (c) Producers, consumers & decomposers

Q. Which of the following could be incinerated?

a) Paper

b) Medicine bottles

c) Needle of the syringe

d) All of the above

Correct Answer: (c) Needle of the syringe

Q. The harmful chemical which is accumulating in human beings through the food chain is

a) BHC

b) DDT

c) Abscisic acid

d) CFC

Correct Answer: (b) CFC

Q. Carnivores represent

a) Primary consumers

b) Reducers

c) Phytoplanktons

d) Secondary and tertiary consumers

Correct Answer: (d) Secondary and tertiary consumers

Q. Biodegradable wastes include

a) Aluminium foils

b) Glass bottles

c) Pesticides

d) Wood shavings

Correct Answer: (d) Wood shavings

Q. What is the most expensive component of solid waste handling?

a) Collection

b) Storage

c) Treatment

d) Separation

Correct Answer: (a) Collection

Q. The most rapidly dwindling natural resource in the world is:

(a) Water

(b) Forest

(c) Wind

(d) Sunlight

Correct Answer: (b) Forest

Q. The three R’s that will help us to conserve natural resources for long-term use are:

(a) Recycle, regenerate, reuse

(b) Reduce, regenerate, reuse

(c) Reduce, reuse, redistribute

(d) Reduce, recycle, reuse

Correct Answer: (d) Reduce, recycle, reuse

Q. Which of the following is not a natural resource?

(a) Mango tree

(b) Snake

(c) Wind

(d) Wooden house

Correct Answer: (d) Wooden house

Q. In which year was the Wildlife Protection Act implemented in India?

(a) 1952

(b) 1962

(c) 1972

(d) 1982

Correct Answer: (c) 1972

Q. Who prepared the Ganga Action Plan?

(a) Department of Pollution

(b) Department of Environment

(c) Department of River

(d) Department of Industries

Correct Answer: (b) Department of Environment

Q. At which of the following places are royal Bengal tigers found?

(a) Mahanadi delta

(b) Godavari delta

(c) Kaveri delta

(d) Sundarban delta

Correct Answer: (d) Sundarban delta

Q. In which of the following states does the Ganga originate?

(a) Jammu and Kashmir

(b) Himachal Pradesh

(c) Uttarakhand

(d) None

Correct Answer: (c) Uttarakhand

Q. Which of the following is not a natural resource?

(a) Soil

(b) Water

(c) Air

(d) Electricity

Correct Answer: (d) Electricity

Q. Which one of the following is the Biosphere Reserve of India?

(a) Gir

(b) Nilgiri

(c) Kanheri

(d) None of the above

Correct Answer: (b) Nilgiri

Q. When was the Ganga Action Plan launched?

(a) 1980

(b) 1982

(c) 1984

(d) 1986

Correct Answer: (d) 1986

Q. The pH range most conducive for the life of freshwater plants and animals is:

(a) 6.5 to 7.5

(b) 2.0 to 3.5

(c) 3.5 to 5.0

(d) 9.0 to 10.5

Correct Answer: (a) 6.5 to 7.5

Q. Tropical rainforests grow well in areas receiving rainfall

(a) 200 cm

(b) 150 cm

(c) 100 cm

(d) 70 cm

Correct Answer: (a) 200 cm

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