In 2021, the CBSE introduced a new exam pattern for Class 10 Science due to the COVID-19 pandemic. The academic session was divided into Term 1 and Term 2, with separate sample papers and board exams for each term.

CBSE Class 10 Science Sample Paper 2021Term 1 & Term 2

Term 1 featured only objective-type questions (MCQs), while Term 2 included short and long answer questions. This format aimed to reduce pressure on students and ensure fair assessment during uncertain times. On this page, you’ll find the complete CBSE Class 10 Science Sample Paper 2021 for both terms, along with detailed, easy-to-understand solutions in plain text format—perfect for board exam preparation.

CBSE Class 10 Science Sample Paper 2021 (Term 1 & Term 2) – Questions and Answers

TERM 1 – Objective Type Questions (MCQs)

Q1. Reema took 5 ml of Lead Nitrate solution in a beaker and added approximately 4 ml of Potassium Iodide solution. What would she observe?
Answer: Yellow precipitate is formed.
This is due to a double displacement reaction:
Pb(NO₃)₂ + 2KI → PbI₂ (yellow precipitate) + 2KNO₃

Q2. A student collected a gas in the setup shown, and the gas turned lime water milky. Identify the gas.
Answer: Carbon dioxide
CO₂ is released during the reaction and it turns lime water milky.

Q3. Which combination of metals will react with acids to release hydrogen gas?
Answer: Iron and Zinc
These are more reactive than hydrogen and displace it from acids. Copper does not react.

Q4. Which of the following statements about acids is correct?
Answer: Acids produce H⁺ ions only in aqueous solutions.
Acids ionize to give H⁺ ions in water, not in dry state.

Q5. What is observed when magnesium ribbon burns in air?
Answer: It burns with a brilliant white light.
Magnesium + Oxygen → Magnesium oxide (white ash)

Q6. A student touches a moist blue and red litmus paper with a solution. Both litmus papers do not change colour. The solution is:
Answer: Neutral
No change on either litmus indicates a neutral solution.

Q7. Identify the correct sequence of energy flow in a food chain.
Answer: Sun → Plants → Herbivores → Carnivores
This is the natural flow from producers to higher trophic levels.

Q8. The process by which green plants make their own food is:
Answer: Photosynthesis
Carbon dioxide + Water → Glucose + Oxygen (in presence of sunlight)

Q9. In human beings, the breakdown of food to release energy occurs in:
Answer: Mitochondria
Known as the powerhouse of the cell where aerobic respiration takes place.

Q10. In the given diagram of a plant leaf cross-section, identify the structure where photosynthesis mainly occurs.
Answer: Palisade cells
These cells are rich in chloroplasts and perform photosynthesis.

Q11. In the human heart, which chamber pumps oxygenated blood into the aorta?
Answer: Left ventricle
The left ventricle sends oxygen-rich blood into the body through the aorta.

Q12. What is the function of platelets in blood?
Answer: Blood clotting
Platelets help seal wounds and prevent excessive bleeding.

Q13. When light passes from air to glass, it:
Answer: Bends towards the normal
Due to change in medium, refraction occurs.

Q14. The focal length of a convex lens is 20 cm. What is its power?
Answer: +5D
Power = 100/f(cm) = 100/20 = +5 dioptres

Q15. Which mirror is used in torches and vehicle headlights?
Answer: Concave mirror
It focuses light into a parallel beam.

Q16. If an object is placed at 2F in front of a convex lens, the image is formed:
Answer: At 2F, real, inverted, same size
A well-known lens property.

Q17. A student obtains a blurred image of a distant tree using a convex lens. To sharpen it, he should:
Answer: Move the lens away from the screen
To get the image at the correct focal point.

Q18. Which part of the human eye controls the size of the pupil?
Answer: Iris
It adjusts the pupil size depending on light.

Q19. Which of the following lenses would be used to correct hypermetropia?
Answer: Convex lens
It helps focus light on the retina.

Q20. The splitting of white light by a prism into seven colours is called:
Answer: Dispersion
Light splits due to different refractive indices of colours.

TERM 2 – Subjective Questions and Answers

Q1.
a. Which elements form covalent bonds with carbon?
b. Why can carbon form many compounds with such elements?
Answer:
a. Nonmetals like hydrogen, oxygen, nitrogen.
b. Carbon is tetravalent and can form strong covalent bonds, allowing multiple bonding patterns.

Q2.
a. Which element among P, Q, R, S, T has a larger atomic radius – W or Z?
b. Explain your choice.
Answer:
a. W has a larger atomic radius.
b. Atomic radius decreases across a period due to increased nuclear charge.

Q3.
Trace the path of the male gamete to the female gamete and state how many chromosome sets a zygote has.
Answer:
Path: Testes → Vas deferens → Urethra → Vagina → Uterus → Fallopian tube
Zygote has two sets of chromosomes (diploid), one from each parent.

Q4.
Identify the organism on moist bread and describe its reproduction.
Answer:
Organism: Rhizopus
Reproduction: Asexual via spore formation. Spores are produced in sporangia.

Q5.
Field A shows same brown seeds; Field B shows yellow seeds. Why the difference?
Answer:
Field A: Asexual reproduction → identical traits
Field B: Sexual reproduction → variation in traits due to recombination

Q6.
a. What is the direction of force on wire AB in a magnetic field?
b. Why does wire BC not contribute to rotation?
Answer:
a. Downward, using Fleming’s left-hand rule
b. Wire BC is parallel to the magnetic field → no magnetic force acts

Q7.
What happens when DDT is sprayed in a lake?
Answer:
DDT accumulates and magnifies up the food chain → harmful effects on fish and birds due to biomagnification

Q8.
Select elements from Period 3 based on properties:
a. Like diamond – Silicon
b. Like lithium – Sodium
c. Variable valency – Sulphur

Q9.
a. Draw isomers of C₄H₈ and name a branched one.
b. State how C₄H₈ and C₅H₁₀ are homologues.
Answer:
a. But-1-ene, But-2-ene, and Methylpropene
b. Differ by CH₂ group; same functional group (alkene)

Q10.
F₁ generation has RrYy; what fraction shows new traits in F₂?
Answer:
Phenotypic ratio: 9:3:3:1
New traits (Round-green and Wrinkled-yellow) = 6/16
If 160 seeds → 60 show new combinations

Q11.
a. Calculate energy cost for 2kW heater used 3 hours/day for 1 day at ₹3.50/unit
b. How to reduce water boiling time using coil wire?
Answer:
a. Energy = 6 units → ₹21
b. Use thicker/shorter wire to reduce resistance and increase current

Q12.
Find total resistance and current in a circuit of 2Ω, 3Ω, and 6Ω resistors.
Answer:
Use parallel and series formulas. Final current calculated using Ohm’s law: I = V/R

Q13.
Name gas A formed by action of UV on oxygen. How is it useful?
Answer:
Gas A: Ozone (O₃)
Protects from harmful UV rays; destroyed by CFCs

Q14.
a. Identify F₁ traits when tall (TT) × dwarf (tt) are crossed.
b. In F₂, calculate number of tall and dwarf plants among 800 total.
Answer:
F₁: All tall (Tt)
F₂: 3:1 → 600 tall, 200 dwarf

Q15.
Explain working of electric generator using magnet and coil. How to increase current?
Answer:
Principle: Electromagnetic induction
Magnet motion induces current in coil
To increase: use stronger magnet or rotate faster

For the official Class 10 Mathematics Solutions, you can visit:

  1. NCERT Textbooks (for Class 10):
ncert resources

Class-wise Solutions

Class 12:

Class 12 Physics – NCERT Solutions

Class 12 Chemistry – NCERT Solutions

Class 11:

Class 10:

Class 9:

Class 8:

Class 7:

Class 6:

Subject-wise Solutions

Physics:

Chemistry:

Biology:

Math:

Science:

NEET BIOLOGY

Practicing with the CBSE Class 10 Science Sample Paper 2021 is one of the smartest ways to prepare for the board exam, especially considering the changed exam pattern due to the COVID-19 pandemic. The division into Term 1 and Term 2 gave students a different experience, and solving both sample papers helps build familiarity with this unique structure. Whether it’s mastering objective-type MCQs or writing accurate descriptive answers, these papers offer the right practice for every section of the syllabus.

The CBSE Class 10 Science Sample Paper 2021 includes well-crafted questions based on real-life applications, case studies, and experimental concepts from Physics, Chemistry, and Biology. With clearly explained answers provided for each question, students can evaluate their preparation and correct their mistakes effectively.

Teachers and tutors can also use the CBSE Class 10 Science Sample Paper 2021 as a revision tool in classrooms or online classes. It serves as a blueprint for understanding the marking scheme and question weightage, helping students write answers as expected by CBSE examiners.

In conclusion, the CBSE Class 10 Science Sample Paper 2021 is more than just a practice tool — it’s a complete guide for exam success. By solving both Term 1 and Term 2 papers with the correct approach, students can strengthen their concepts, improve answer-writing skills, and gain the confidence needed to score high marks in the final board exam.