Physics Mock Test 1 Practice

1. Which of the following is a fundamental (base) unit in the SI system?

• A. Newton
• B. Joule
• C. Kilogram (Correct)
• D. Pascal

Explanation: The SI system has 7 base units. Kilogram (kg) is the base unit of mass. Newton, Joule, and Pascal are derived units.

2. The value of cos 60° is:

• A. √3/2
• B. 1/2 (Correct)
• C. 0
• D. 1

Explanation: cos 60° = 1/2 . Standard values: cos 0° = 1, cos 30° = √3/2, cos 45° = 1/√2, cos 60° = 1/2, cos 90° = 0.

3. Average speed is defined as:

• A. Total displacement/total time
• B. Total distance/total time (Correct)
• C. Change in velocity/time
• D. Final velocity − initial velocity

Explanation: Average speed = total distance / total time . It is a scalar. Average velocity = total displacement / total time.

4. A projectile is fired horizontally from height h. The time to reach ground is:

• A. √(h/g)
• B. √(2h/g) (Correct)
• C. 2h/g
• D. h/g

Explanation: h = ½gt² → t = √(2h/g) .

5. The impulse of a force is defined as:

• A. Force × distance
• B. Force × acceleration
• C. Force × time (Correct)
• D. Force × velocity

Explanation: Impulse J = Force × time = F·Δt. Impulse equals the change in momentum: J = Δp.

6. Work done by gravity on ball dropped from height h:

• A. mgh (Correct)
• B. −mgh
• C. 0
• D. ½mv²

Explanation: Force and displacement both downward. W = mgh .

7. Angular displacement θ (in rad) for a wheel: θ = 2t³ + 3t. Angular velocity at t = 2 s:

• A. 27 rad/s (Correct)
• B. 24 rad/s
• C. 30 rad/s
• D. 12 rad/s

Explanation: ω = dθ/dt = 6t² + 3. At t=2: ω = 6×4+3 = 27 rad/s .

8. A tunnel through Earth's diameter — period of oscillation of body in tunnel:

• A. Same as satellite period
• B. √(R/g) s
• C. 2π√(R/g) s (Correct)
• D. Depends on amplitude

Explanation: Body in tunnel undergoes SHM with T = 2π√(R/g) ≈ 84 min = 2π√(R/g) .

9. For same material, if cross-sectional area doubles (same L, F), the extension:

• A. Doubles
• B. Halves (Correct)
• C. Stays same
• D. Quadruples

Explanation: ΔL = FL/AY. If A→2A, ΔL → ΔL/2 = halves .

10. A floating body displaces fluid equal in weight to:

• A. Half its weight
• B. Twice its weight
• C. Its own weight (Correct)
• D. Volume of body

Explanation: Floating equilibrium: buoyant force = weight. Fluid displaced = its own weight .

11. In a NEET physics drill, a particle starts with speed 5 m/s and acceleration 2 m/s^2 for 3 s. Final speed is:

• A. 11 m/s (Correct)
• B. 9 m/s
• C. 13 m/s
• D. 15 m/s

Explanation: Use v = u + at = 5 + 2 x 3 = 11 m/s.

12. The SI unit of electric current is:

• A. Volt
• B. Ampere (Correct)
• C. Coulomb
• D. Ohm

Explanation: Ampere (A) is the SI base unit of electric current. Coulomb is the unit of charge, Volt is the unit of potential difference, and Ohm is the unit of resistance — all derived.

13. Two forces of 3 N and 4 N act at right angles to each other. The resultant force is:

• A. 7 N
• B. 5 N (Correct)
• C. 1 N
• D. 12 N

Explanation: For perpendicular forces: R = √(3² + 4²) = √25 = 5 N . This is the classic 3-4-5 right triangle.

14. In a position-time graph, a horizontal straight line indicates:

• A. Uniform velocity
• B. Non-uniform velocity
• C. Body at rest (Correct)
• D. Uniform acceleration

Explanation: A horizontal line on a position-time graph means position is constant. The body is at rest . Slope = velocity = 0.

15. The period T and angular velocity ω are related by:

• A. T = ω/2π
• B. T = 2π/ω (Correct)
• C. T = 2πω
• D. T = ω

Explanation: ω = 2π/T, therefore T = 2π/ω .

16. The coefficient of friction is the ratio of:

• A. Force to mass
• B. Friction force to normal force (Correct)
• C. Normal force to friction
• D. Weight to volume

Explanation: μ = f/N = friction force / normal force . It is dimensionless.

17. Momentum increased by 20%. Percentage increase in KE:

• A. 40%
• B. 44% (Correct)
• C. 20%
• D. 10%

Explanation: KE ∝ p². p→1.2p: KE→1.44KE. Increase = 44% .

18. Three equal masses m at vertices of equilateral triangle (side a). COM from any vertex:

• A. a/√3 (Correct)
• B. a/2
• C. a√3/3
• D. a/3

Explanation: COM of equilateral triangle with vertices at (0,0), (a,0), (a/2, a√3/2) is at (a/2, a√3/6). Distance from vertex = a/√3 = a/√3 .

19. Gravitational field due to a point mass at distance r varies as:

• A. r
• B. r²
• C. 1/r
• D. 1/r² (Correct)

Explanation: g = GM/r² ∝ 1/r² .

20. Bulk modulus B is defined as:

• A. Longitudinal stress/Longitudinal strain
• B. Shear stress/Shear strain
• C. Volumetric stress/Volumetric strain (Correct)
• D. Force/Area

Explanation: B = Volumetric stress / Volumetric strain = −P/(ΔV/V).

21. Object (density ρ_obj) floats in fluid (density ρ_f). Fraction submerged:

• A. ρ_f/ρ_obj
• B. ρ_obj/ρ_f (Correct)
• C. ρ_obj×ρ_f
• D. 1 − ρ_obj/ρ_f

Explanation: At equilibrium: ρ_obj×V×g = ρ_f×V_sub×g. V_sub/V = ρ_obj/ρ_f .

22. A block of mass 3 kg accelerates at 3 m/s^2. Net force on it is:

• A. 12 N
• B. 6 N
• C. 15 N
• D. 9 N (Correct)

Explanation: By Newton's second law, F = ma = 3 x 3 = 9 N.

23. The dimensions of velocity are:

• A. [MLT⁻¹]
• B. [LT⁻¹] (Correct)
• C. [ML²T⁻²]
• D. [LT⁻²]

Explanation: Velocity = displacement / time = L / T = [LT⁻¹] . It has no mass dimension.

24. If two equal vectors of magnitude A are inclined at angle θ to each other, the magnitude of their resultant is:

• A. 2A cosθ
• B. 2A cos(θ/2) (Correct)
• C. A cos(θ/2)
• D. 2A sinθ

Explanation: For two equal vectors of magnitude A at angle θ: R = A√(2+2cosθ) = A√(4cos²(θ/2)) = 2A cos(θ/2) .

25. A car accelerates from 0 to 20 m/s in 5 seconds. Its acceleration is:

• A. 100 m/s²
• B. 25 m/s²
• C. 4 m/s² (Correct)
• D. 0.25 m/s²

Explanation: a = (v−u)/t = (20−0)/5 = 4 m/s² .

26. The horizontal component of velocity of a projectile during flight:

• A. Increases continuously
• B. Decreases continuously
• C. Remains constant (Correct)
• D. First increases then decreases

Explanation: In absence of air resistance, no horizontal force acts. By Newton's first law, horizontal velocity remains constant .

27. The law of conservation of momentum states total momentum is conserved when:

• A. Net external force is maximum
• B. Net external force is zero (Correct)
• C. Internal forces are zero
• D. All objects are at rest

Explanation: Total momentum is conserved when net external force is zero .

28. Spring (k = 200 N/m) compressed by 0.1 m. Work done in compressing:

• A. 2 J
• B. 1 J (Correct)
• C. 0.5 J
• D. 4 J

Explanation: W = ½kx² = ½ × 200 × 0.01 = 1 J .

29. A couple consists of two forces. Net force of a couple:

• A. 2F
• B. F
• C. Zero (Correct)
• D. F²

Explanation: A couple consists of two equal and opposite forces — net force = zero , but torque ≠ 0.

30. Gravitational force is weakest of four fundamental forces. Relative strength compared to electromagnetic:

• A. 10³⁶ times weaker (Correct)
• B. 10⁶ times weaker
• C. Same strength
• D. Slightly weaker

Explanation: Gravity is approximately 10³⁶ times weaker than electromagnetic force.