CLASS: XI – Physics Mid Term Examination (2025-26)

CLASS: XI – Physics Mid Term Examination (2025-26)

St. Margaret Sr. Sec. School, Prashant Vihar, Sector-14, Rohini, Delhi-85, India

Class:	11th Standard (CBSE)
Subject:	Physics
Set:	SET – B
Time Duration:	03 Hours
Maximum Marks:	70

General Instructions:

1. There are 33 questions in all. All questions are compulsory.
2. This question paper has five sections: Section A, Section B, Section C, Section D and Section E.
3. Internal choices are provided in some questions — attempt only one option where applicable.
4. Use of calculators is not allowed.

SECTION – A (1×16)

Q1. The number of significant digits in 0.400 is

• (a) 1 (b) 2 (c) 3 (d) 4

Q2. For (P + a/V²)(V − b) = RT, the dimension of constant a is

• (a) [MLT⁻¹] (b) [ML⁻⁵T] (c) [M²L⁵T⁻¹] (d) [ML⁵T⁻²]

Q3. The dimensions of impulse are equal to that of

• (a) pressure (b) force (c) linear momentum (d) angular momentum

Q4. The variation of quantity A with B (as shown in figure) describes motion in a straight line. Then:

• (a) A is displacement if motion is uniform
• (b) A is distance if motion is uniformly accelerated
• (c) A is velocity if motion is uniform
• (d) None of the above

Q5. If displacement ∝ t², the object moves with

• (a) constant acceleration (b) uniform motion (c) constant velocity (d) non-uniform motion

Q6. Angle between centripetal and tangential acceleration is

• (a) 180° (b) 0° (c) 90° (d) 45°

Q7. Minimum number of vectors in different planes to give zero resultant

• (a) 2 (b) 3 (c) 4 (d) 5

Q8. A stone is projected at 30°. Ratio of KE at projection to KE at highest point

• (a) 4:1 (b) 1:2 (c) 4:3 (d) 1:4

Q9. A jet engine works on conservation of

• (a) linear momentum (b) angular momentum (c) energy (d) mass

Q10. A balloon with 5 g of air leaks at 4 cm/s and shrinks in 2.5 s. Average force is

• (a) 2 dyne (b) 2 N (c) 8 dyne (d) 8 N

Q11. A 2 m pendulum is released from 60°. The speed at lowest point is

• (a) √(2g×9.8) (b) √2g (c) 4.43 m/s (d) 1 m/s

Q12–Q16 Assertion–Reason Questions (Options: A, B, C, D)

Q12. Assertion: A man doing same work in less time develops more power. Reason: Momentum is larger in first case.

Q13. Assertion: Energy cannot be divided by volume. Reason: Their dimensions differ.

Q14. Assertion: Uniform motion may have negative slope in x–t graph. Reason: Position may reverse.

Q15. Assertion: Maximum range ∝ v². Reason: Maximum range = maximum height.

Q16. Assertion: Quick collision is more violent than slow one. Reason: Impulse larger in first case.

SECTION – B (2×5)

Q17. Distinguish between dimensional and non-dimensional constants.

Q18. Two balls: A upward at 25 m/s, B downward from 50 m with 25 m/s — find collision point (g = 9.8 m/s²).

Q19. Find horizontal and vertical components of acceleration of a projectile.

Q20. One bullet dropped, one fired horizontally — which hits first and why?

Q21. A ball with momentum 5 kg·m/s strikes a wall at 45° and rebounds at same angle — find impulse.

SECTION – C (3×7)

Q22. A block has dimensions 16.2 cm × 8.2 cm × 2.40 cm — find volume in correct significant figures.

Q23. For x = 3t³ − 6t² − 15t + 40, find (a) time when v = 0, (b) position & displacement, (c) acceleration.

Q24. State and prove parallelogram law of vector addition.

Q25. Three blocks m₁ = 5 kg, m₂ = 10 kg, m₃ = 15 kg pulled by F = 50 N — find tensions T₁ and T₂.

Q26. Deduce that angle of repose = angle of friction. OR explain practical applications.

Q27. If kinetic energy increases by 300%, find percentage increase in linear momentum.

SECTION – D (Case Study – 4 Marks)

Q28. Projectile motion: x = (u cosθ)t, y = (u sinθ)t − ½gt²; vₓ = u cosθ; vᵧ = u sinθ − gt; aₓ = 0; aᵧ = −g — answer the related MCQs.

SECTION – E (5×3)

Q29. Springs and elastic potential energy — answer questions on ratios, zero PE, work, and energy change.

Q30. (i) Spring constant ratio 2:3 — find ratio of potential energy for same force. (ii) U(x)=0, extra stretch work, PE change.

Q31. A person of mass m in a lift — find apparent weight for upward motion, downward motion (a<g), and free fall. OR use force–time graph to find impulse and force.

Q32. Derive equations of motion (graphically / analytically). OR state & prove Work–Energy Theorem; define non-conservative force.

Q33. Prove that for elastic collision e = 1 and for equal masses in 1-D collision, velocities exchange.