Class 10 Science Most Important Questions

MCQs :

1. What is the chemical equation for the roasting of zinc blende (ZnS)?

A) 2ZnS+3O2→2ZnO+2SO2
B) ZnS+O2→Zn+SO2
C) ZnS+2O2→ZnSO4​
D) ZnS+O2→ZnO+S

2. What is the main purpose of reproduction in living organisms?

A) To obtain food
B) To increase the size of the organism
C) To produce offspring and ensure the continuation of the species
D) To get rid of waste

3. Gustatory receptors are present in which of the following?

A) Eyes
B) Ears
C) Nose
D) Tongue

4. When light enters the atmosphere and strikes extremely fine particles, which deflect rays of light in all possible directions, this is due to?

A) Refraction of light
B) Reflection of light
C) Dispersion of light
D) Scattering of light

5. Myopia is a condition in which a person:

A) Can see distant objects clearly
B) Can see nearby objects clearly
C) Needs a concave lens to correct vision
D) Needs a convex lens to correct vision

6. Baking soda is chemically known as:

A) Sodium carbonate (Na₂CO₃)
B) Sodium bicarbonate (NaHCO₃)
C) Potassium bicarbonate (KHCO₃)
D) Calcium bicarbonate (Ca(HCO₃)₂)

7. Soda ash is another name for:

A) Calcium hydroxide
B) Sodium carbonate (Na₂CO₃)
C) Sodium bicarbonate
D) Potassium hydroxide

8. What is the chemical equation for the esterification reaction between acetic acid (CH₃COOH) and ethanol (CH₃CH₂OH)?

A) CH3COOH+CH3CH2OH→CH3COOCH3+H2O
B) CH3COOH+CH3CH2OH→H2SO4CH3COOCH2CH3+H2O
C) CH3COOH+CH3CH2OH→CH3COOH+CH3CH2OH
D) CH3COOH+CH3CH2OH→CH3COOCH2CH3

9. What is meant by resistance and what is its SI unit?

A) Resistance is the opposition to the flow of electric current, and its SI unit is Ampere.
B) Resistance is the opposition to the flow of electric current, and its SI unit is Ohm.
C) Resistance is the flow of electric charge, and its SI unit is Volt.
D) Resistance is the amount of current flowing in a conductor, and its SI unit is Coulomb.

10. Which of the following is the SI unit of force?

A) Watt
B) Joule
C) Newton
D) Ampere

11. Which of the following reactions is an example of a Redox (Oxidation-Reduction) reaction?

A) H2+Cl2→2HCl
B) NaCl+AgNO3→NaNO3+AgCl
C) CuO+H2→Cu+H2O
D) Fe2O3+3CO→2Fe+3CO2

12. Washing soda is also known as:

A) Sodium carbonate (Na₂CO₃)
B) Sodium bicarbonate (NaHCO₃)
C) Calcium carbonate (CaCO₃)
D) Potassium carbonate (K₂CO₃)

13. The chemical formula of washing soda is:

A) Na₂CO₃·10H₂O
B) NaHCO₃
C) Na₂CO₃
D) Na₂SO₄

14. What is the chemical equation for the calcination of zinc carbonate (ZnCO₃) when heated with carbon?

A) ZnCO3+C→Zn+CO2+CO
B) ZnCO3→ZnO+CO2​
C) ZnCO3+O2→ZnO+CO2​
D) ZnCO3+C→ZnO+CO+CO2

15. In a cross between a homozygous dominant (RR) and a homozygous recessive (rr) organism, what is the genotype of all the offspring?

A) Rr
B) RR
C) rr
D) Rr and rr

16. Generally, food is broken down and absorbed within the body. In which of the following organisms does this process occur outside the body?

A) Amoeba
B) Mushroom
C) Paramecium
D) Lice

17. Which of the following features relates to biodegradable substances?

A) Can be broken down by microorganisms
B) Can never decompose
C) Harmful to the environment
D) Does not require any natural processes for decomposition

18. Which of the following is the correct lens formula?

A) 1 / f = 1 / v − 1 / u​
B) 1 / f = 1 / u − 1 / v​
C) 1 / f = 1 / v + 1 / u​
D) 1 / f = 1 / v − 1 / u​​

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

A) Zero
B) Decreases as we move towards its end
C) Increases as we move towards its end
D) Is the same at all points

20. Which of the following lenses is used to correct hypermetropia?

A) Convex lens
B) Concave lens
C) Plane mirror
D) Bifocal lens

Correct Answers :

Important Questions : 

Chapter 1: Chemical Reactions and Equations

1. What are the different types of chemical reactions?
2. How do you balance a chemical equation?
3. What is the law of conservation of mass?
4. Define oxidation and reduction reactions.
5. What are exothermic and endothermic reactions?
6. Explain the significance of precipitation reactions.
7. How can you identify a displacement reaction?

Chapter 2: Acids, Bases and Salts

1. What are the properties of acids and bases?
2. How is pH related to the strength of acids and bases?
3. Describe the process of neutralization.
4. What are common uses of salts in daily life?
5. How do indicators help in identifying acids and bases?
6. Explain the concept of a strong acid versus a weak acid.
7. What is the role of water in the acidic or basic nature of substances?

Chapter 3: Metals and Non-metals

1. What are the physical properties of metals and non-metals?
2. How do metals react with acids?
3. Explain the process of extraction of metals from their ores.
4. What is the reactivity series of metals?
5. Describe the formation of ionic bonds between metals and non-metals.
6. What are alloys, and why are they important?
7. How do non-metals participate in covalent bonding?

Chapter 4: Carbon and its Compounds

1. What is catenation, and why is it significant in carbon compounds?
2. Explain the difference between saturated and unsaturated hydrocarbons.
3. How do you name organic compounds using IUPAC nomenclature?
4. What are functional groups in organic chemistry?
5. Describe the process of soap formation (saponification).
6. What are isomers, and how do they differ from each other?
7. Explain the concept of homologous series in carbon compounds.

Chapter 5: Life Processes

1. What are the essential life processes in living organisms?
2. How does the human digestive system function?
3. Explain the process of respiration in plants and animals.
4. What is the role of the circulatory system in humans?
5. How do plants perform photosynthesis?
6. Describe the process of excretion in humans.
7. What is the significance of transpiration in plants?

Chapter 6: Control and Coordination

1. How does the human nervous system function?
2. What are hormones, and what role do they play in animals?
3. Explain the mechanism of reflex actions.
4. How do plants respond to external stimuli?
5. What is the difference between voluntary and involuntary actions?
6. Describe the structure and function of neurons.
7. How does the endocrine system regulate bodily functions?

Chapter 7: How do Organisms Reproduce?

1. What are the different modes of asexual reproduction?
2. How does sexual reproduction occur in flowering plants?
3. Explain the human reproductive system.
4. What is the significance of DNA replication in reproduction?
5. How do organisms ensure the continuity of species?
6. What are sexually transmitted diseases, and how can they be prevented?
7. Describe the process of fertilization in humans.

Chapter 8: Heredity

1. What is Mendel’s law of inheritance?
2. How do dominant and recessive traits differ?
3. Explain the concept of genotype and phenotype.
4. What is the role of chromosomes in heredity?
5. How does genetic variation occur in a population?
6. Describe the process of sex determination in humans.
7. What are genetic disorders, and how are they inherited?

Chapter 9: Light – Reflection and Refraction

1. What are the laws of reflection of light?
2. How does refraction occur when light passes through different media?
3. Explain the formation of images by concave and convex mirrors.
4. What is the refractive index, and how is it calculated?
5. Describe the functioning of lenses in image formation.
6. How do optical instruments like microscopes and telescopes work?
7. What causes the dispersion of light into its constituent colors?

Chapter 10: The Human Eye and the Colourful World

1. Explain the structure and function of the human eye.
2. What is the power of accommodation of the eye?
3. Define myopia and hypermetropia. How can they be corrected?
4. What causes the twinkling of stars?
5. Why does the sky appear blue during the day and reddish at sunrise and sunset?
6. Describe the phenomenon of dispersion of light through a prism.
7. What is the cause of rainbow formation?

Chapter 11: Electricity

1. State Ohm’s Law and its mathematical expression.
2. Define electric power. How is it related to voltage and current?
3. Differentiate between series and parallel circuits.
4. What factors affect the resistance of a conductor?
5. Explain the heating effect of electric current with examples.
6. How do you calculate the total resistance in a series circuit?
7. What is the significance of the electric fuse in household circuits?

Chapter 12: Magnetic Effects of Electric Current

1. Describe the magnetic field around a current-carrying conductor.
2. What is the principle of an electric motor?
3. Explain electromagnetic induction.
4. How does a solenoid behave like a bar magnet?
5. What are the factors affecting the strength of an electromagnet?
6. State Fleming’s Left-Hand Rule and its application.
7. Differentiate between AC and DC currents.

Chapter 13: Our Environment

1. What are biodegradable and non-biodegradable substances? Give examples.
2. Explain the concept of food chains and food webs with examples.
3. What is biological magnification? How does it affect ecosystems?
4. Discuss the role of decomposers in the environment.
5. What are the causes and consequences of ozone layer depletion?
6. How can we reduce the generation of waste in our daily lives?
7. Explain the significance of the 3Rs (Reduce, Reuse, Recycle) in waste management.