Physics MCQ Practice 16 — Science Foundation Course for Class 11 & 12

1. A ball is thrown vertically upward with velocity 40 m/s. The maximum height reached (g=10 m/s²) is:

(a) 40 m (b) 80 m (c) 160 m (d) 200 m

Show Answer & Explanation

Correct Answer: (b) 80 m

Explanation:
H = u²/(2g) = 1600 / 20 = 80 m

2. The weight of a body is 200 N on Earth. Its weight on Moon (g_moon = g/6) is:

(a) 200 N (b) 1200 N (c) 33.3 N (d) 100 N

Show Answer & Explanation

Correct Answer: (c) 33.3 N

Explanation:
Weight on Moon = 200 / 6 ≈ 33.3 N

3. Two capacitors of 4 μF and 12 μF in series. Equivalent capacitance is:

(a) 16 μF (b) 3 μF (c) 48 μF (d) 8 μF

Show Answer & Explanation

Correct Answer: (b) 3 μF

Explanation:
1/C = 1/4 + 1/12 = 1/3 → C = 3 μF

4. The speed of sound in air is 340 m/s. The distance between two consecutive compressions (wavelength) at 680 Hz is:

(a) 0.5 m (b) 1 m (c) 2 m (d) 0.25 m

Show Answer & Explanation

Correct Answer: (a) 0.5 m

Explanation:
λ = v/f = 340 / 680 = 0.5 m

5. The force on a moving charge in magnetic field is zero when:

(a) Velocity parallel to B (b) Velocity perpendicular to B (c) Charge is zero (d) Both (a) and (c)

Show Answer & Explanation

Correct Answer: (d) Both (a) and (c)

Explanation:
F = q(v × B) = 0 when v parallel to B or q=0

6. A concave mirror of focal length 15 cm forms a virtual image at 30 cm. The object distance is:

(a) 30 cm (b) 10 cm (c) 20 cm (d) 45 cm

Show Answer & Explanation

Correct Answer: (b) 10 cm

Explanation:
1/v + 1/u = 1/f calculation gives u = -10 cm

7. In a purely capacitive AC circuit, the phase difference between voltage and current is:

(a) 0° (b) 90° (current leads) (c) 90° (current lags) (d) 180°

Show Answer & Explanation

Correct Answer: (b) 90° (current leads)

Explanation:
Current leads voltage by 90° in capacitor

8. The energy released per fission of U-235 is approximately:

(a) 200 MeV (b) 20 MeV (c) 2 MeV (d) 2000 MeV

Show Answer & Explanation

Correct Answer: (a) 200 MeV

Explanation:
Typical energy released in U-235 fission is ~200 MeV

9. If the length of a simple pendulum is decreased by 4%, the percentage change in time period is:

(a) 2% decrease (b) 4% decrease (c) 2% increase (d) No change

Show Answer & Explanation

Correct Answer: (a) 2% decrease

Explanation:
T ∝ √L → 4% decrease in L → 2% decrease in T

10. The SI unit of magnetic permeability (μ₀) is:

(a) H/m (b) N A⁻² (c) Both (a) and (b) (d) Wb/m

Show Answer & Explanation

Correct Answer: (c) Both (a) and (b)

Explanation:
μ₀ = 4π × 10⁻⁷ H/m = N A⁻²