CBSE 10th Science Exam 2024: Final Topic-Wise Most Important Questions For Last Minute Revision

Multiple Choice Question 

1. In which of the following equations, the mass is not same on both the sides?

(a) Word equation
(b) Skeletal equation
(c) Balanced equation
(d) Both (a) and (b)

Ans. (d) Both (a) and (b)

2. Some reactions require conditions like specific temperature, pressure, etc. While writing chemical equations for such reactions, where are these conditions usually mentioned?

(a) Above the arrow
(b) Along with products
(c) Below the plus signs
(d) Before the reactants

Ans. (a) Above the arrow

3. On adding dilute HCl to copper oxide in a beaker, the solution turns blue green due to formation of

(a) copper(II) hydroxide
(b) copper nitrate
(c) copper (II) chloride
(d) copper sulphate

Ans. (c) copper (II) chloride

4. Calcium carbonate is the chemical formula of

(a) limestone
(b) chalk
(c) marble
(d) all (a), (b) and (c)

Ans. (d) all (a), (b) and (c)

5. Which among the following statements is incorrect for magnesium metal?

(a) It burns in oxygen with a dazzling white flame.
(b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas.
(c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas.
(d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas.

Ans. (b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas.

6. Upon receiving a signal, the dendrite tip of a nerve cell sets off a chemical reaction that

(a) creates an electrical impulse in the dendrite.
(b) creates an electrical impulse in the next neuron.
(c) releases some chemicals in the cell body of the neuron.
(d) creates a stimulus.

Ans. (a) creates an electrical impulse in the dendrite.

7. Dwarfism in human beings is caused due to deficiency of

(a) thyroxin
(b) growth hormone
(c) adrenalin
(d) insulin

Ans. (b) growth hormone

8. Which of the following statements is correct about receptors?

(a) Gustatory receptors detect taste while olfactory receptors detect smell.
(b) Both gustatory and olfactory receptors detect smell.
(c) Auditory receptors detect smell and olfactory receptors detect test.
(d) Olfactory receptors detect taste and gustatory receptors smell.

Ans. (a) Gustatory receptors detect taste while olfactory receptors detect smell.

9. In a flower, the parts that produce male and female gametes (germ cells) are

(a) stamen and anther
(b) filament and stigma
(c) anther and ovary
(d) stamen and style

Ans. (c) anther and ovary

10. Which of the following is the correct sequence of events of sexual reproduction in a flower?

(a) pollination, fertilisation, seedling, embryo
(b) seedling, embryo, fertilisation, pollination
(c) pollination, fertilisation, embryo, seedling
(d) embryo, seedling, pollination, fertilisation.

Ans. (c) pollination, fertilisation, embryo, seedling

11. In Spirogyra, asexual reproduction takes place by

(a) breaking up of filaments into smaller bits
(b) division of a cell into two cells
(c) division of a cell into many cells
(d) formation of young cells from older cells

Ans. (a) breaking up of filaments into smaller bits

12. Exchange of genetic material takes place in

(a) vegetative reproduction
(b) asexual reproduction
(c) sexual reproduction
(d) budding

Ans. (c) sexual reproduction

13. Which of the following statement is incorrect?

(a) For every hormone there is a gene.
(b) For every protein there is a gene.
(c) For production of every enzyme there is a gene.
(d) For every molecule of fat there is a gene.

Ans. (d) For every molecule of fat there is a gene.

14. The maleness of a child is determined by

(a) the X chromosome in the zygote.
(b) the Y chromosome in zygote.
(c) the cytoplasm of germ cell which determines the sex.
(d) sex is determined by chance.

Ans. (b) the Y chromosome in zygote.

15. Humans have two different sex chromosomes, X and Y. Based on the Mendel's laws, a male offspring will inherit which combination of chromosomes?

(a) both the X chromosomes from one of its parents
(b) both the Y chromosomes from one of its parents
(c) combination of X chromosomes from either of its parents
(d) combination of X and Y chromosome from either of its parents

Ans. (d) combination of X and Y chromosome from either of its parents

16. Two lenses of power +2.50 D and -3.75 D are combined to form a compound lens. Its focal length in cm will be

(a) 40
(b)-40
(c) 80
(d) -80

Ans. (d) -80

17. As a ray of light entered medium P from medium Q, its velocity increased. What can be said about the refractive index of medium P as compared to that of the medium Q?

(a) It is lower.
(b) It is higher.
(c) It is the same.
(d) Nothing can be said without knowing what medium P and medium Q are.

Ans. (a) It is lower.

18. The full length image of a distant tall building can definitely be seen by using

(a) a concave mirror
(b) a convex mirror
(c) a plane mirror
(d) both concave as well as plane mirrors

Ans. (b) a convex mirror

19. The most rapidly dwindling natural resource in the world is

(a) water
(b) forests
(c) wind
(d) sunlight

Ans. (b) forests

20. The pH range most conducive for life of fresh water plants and animals is

(a) 6.5-7.5
(b) 2.0-3.5
(c) 3.5-5.0
(d) 9.0-10.5

Ans. (a) 6.5-7.5

21. Select the wrong statement.

(a) Forests provide variety of products.
(b) Forests have greater plant diversity.
(c) Forests do not conserve soil.
(d) Forests conserve water.

Ans. (c) Forests do not conserve soil.

22. Arabari forests of Bengal is dominated by

(a) Tea
(b) Sal
(c) Bamboo
(d) Mangroove

Ans. (b) Sal

23. Opposition to the construction of large dams is due to

(a) social reasons
(b) economic reasons
(c) environmental reasons
(d) all the above

Ans. (d) all the above

24. Bandharas and Tals are age old water harvesting concepts/structures found in

(a) Bihar
(b) Maharashtra
(c) Tamil Nadu
(d) Rajasthan

Ans. (b) Maharashtra

25. The major ill effect of mono culture practice in forests is on the

(a) biodiversity which faces large destruction
(b) local people whose basic needs can no longer be met from such forests
(c) industries
(d) forest department

Ans. (a) biodiversity which faces large destruction

26. The Reni village of Garhwal is famous for

(a) monocultures of pine, teak and eucalyptus
(b) Chipko Movement
(c) extensive biodiversity
(d) participation of local people in efficient management of forests

Ans. (b) Chipko Movement

27. A student studies that we should switch off unnecessary lights and fans in order to save the environment. How does switching off unnecessary electrical appliances help the environment?

(a) It reduces the wastage of energy
(b) It generates electricity when switched off
(c) It recycles the amount of energy used
(d) It increases the efficiency of the electrical appliances

Ans. (a) It reduces the wastage of energy

28. Which of these is an example of sustainable development in order to conserve natural resources for the future generation?

(a) cleaning water resources
(b) finding alternate fuel reservoirs
(c) clearing forests to set up new industries
(d) planning for safe disposal of wastes after mining

Ans. (d) planning for safe disposal of wastes after mining

Assertion-Reason Question 

The following questions consist of two statements — Assertion (A) and Reason (R). Answer these questions selecting the appropriate option 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.

1. Assertion (A) : Brown fumes are produced when lead nitrate is heated.
Reason (R) Nitrogen dioxide gas is produced as a by product due to the decomposition of lead nitrate.

Ans. (a) Both A and R are true and R is the correct explanation of A. 

2. Assertion(A)The acid must always be added to water with constant stirring.
Reason (R) Mixing of an acid with water decreases the concentration of H+ ions per unit volume.

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

3. Assertion (A) Cyton region of nerve fibre collects information for the brain.
Reason (R) Nerve fibres can either have or lack myelin sheath.

Ans. (a) Both A and R are true and R is the correct explanation of A.

4. Assertion (A) Animals can react to stimuli in different ways.
Reason (R): All animals have a nervous system and an endocrine system involving hormones.

Ans. (a) Both A and R are true and R is the correct explanation of A.

5. Assertion(4) The effect of auxin hormone on the growth of root is exactly opposite to that on a stem.
Reason (R) Auxin hormone increases the rate of growth in root and decreases the rate of growth in stem.

Ans. (c) A is true but R is false.

6. Assertion(A) Asexual reproduction is a primitive type of reproduction.
Reason (R) Asexual reproduction involves only mitotic cell division.

Ans. (a) Both A and R are true and R is the correct explanation of A.

7. Assertion (4): Clones are offspring of an organism formed by asexual reproduction.
Reason (R): Clones have exact copies of DNA as their parent.

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

8. Assertion(4) Pollen grains from the carpel stick to the stigma of stamen.
Reason (R): The fertilised egg cells grow inside the ovules and become seeds.

Ans. (d) A is false but R is true.

9. Assertion(A) Testes lie in penis outside the body.
Reason (R) Sperms require temperature lower than the body temperature for development.

Ans. (d) A is false but R is true.

10. Assertion(A) Light does not travel in the same direction in all the media.
Reason (R): The speed of light does not change as it enters from one transparent medium to another.

Ans. (c) A is true but R is false.

11. Assertion(4) Mirror formula can be applied to a plane mirror.
Reason (R): A plane mirror is a spherical mirror of infinite focal length.

Ans. (a) Both A and R are true and R is the correct explanation of A.

12. Assertion (4): Refractive index has no units.
Reason (R) The refractive index is a ratio of two similar quantities.

Ans. (a) Both A and R are true and R is the correct explanation of A.

13. Assertion(A) Dams cause discontentment among people.
Reason (R) Local people are alienated from their land without adequate compensation.

Ans. (a) Both A and R are true and R is the correct explanation of A.

14. Assertion(A) : Natural resources need to be used carefully.
Reason (R) : Resources are finite in supply and human population is tremendously increasing.

Ans. (a) Both A and R are true and R is the correct explanation of A.

Very Short Answer Question 

Q. 1. What does the word aqueous (aq) represent in a chemical reaction?

Ans. It represents that the compound is present as a solution in water.

Q. 2. Two solutions X and Y have pH values of 3.0 and 9.5 respectively. Which of these will turn litmus solution from blue to red and which will turn phenolphthalein from colourless to pink?

Ans. X will turn blue litmus to red because it is acidic in nature having pH value less than 7. Y will turn phenolphthalein from colourless to pink because it is basic in nature having pH value greater than 7.

Q.3. Which hormone regulates the concentration of sugar in the blood?

Ans. Insulin secreted by islets of Langerhans of pancreas.

Q. 4. What is the function of pollen grains in flowers?

Ans. Pollen grains are the male gametes which fertilise the egg cell present in the ovule of a flower.

Q. 5. Explain the role of cotyledon and plumule in germination.

Ans. Cotyledon stores food and the plumule acts as future shoot.

Q. 6. What is menopause?

Ans. The period of permanent cessation of menstruation in females, usually occurring between the age of 45 and 50 is called as menopause.

Q. 7. What is syngamy?

Ans. One male gamete fuses with one female gamete or egg. This process of fusion of male and female nuclei is called syngamy.

Q. 8. Define alleles.

Ans. Genes which code for a pair of contrasting traits are known as alleles, i.e., they are the different forms of the same gene.

Q.9. Which of the following traits are recessive in pea plant? Dwarfness, violet flower, wrinkled seed.

Ans. Dwarfness and wrinkled seeds are the recessive characters.

Q. 10. Give reasons for the appearance of new combinations of characters in the F₂ progeny.

Ans. The tall/short and round/wrinkled seed trait are independently inherited.

Q. 11. What is light?

Ans. Light is a form of energy which gives us the sensation of sight or vision.

Q. 12. We often use the word environment. What does it mean?

Ans. Environment is the physical, chemical and biological conditions of the region.

Q. 13. Name the award given in the memory of Amrita Devi Bishnoi.

Ans. Amrita Devi Bishnoi award for wildlife conservation

Q. 14. What are biodiversity hotspots?

Ans. Biodiversity hotspots: are regions rich in biodiversity.