Physics MCQ Practice 10 — Science Foundation Course for Class 11 & 12

1. A particle moves with uniform acceleration. The displacement in the nth second is given by:

(a) u + (a/2)(2n-1) (b) u + an (c) (1/2)an ² (d) ut

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Correct Answer: (a) u + (a/2)(2n-1)

Explanation:
Standard formula for displacement in nth second

2. The escape velocity on a planet is v. If mass and radius are both doubled, new escape velocity is:

(a) v (b) 2v (c) v/2 (d) √2 v

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Correct Answer: (a) v

Explanation:
v_esc = √(2GM/R). Both M and R doubled → ratio same → v remains v

3. Two point charges +q and -q are placed 2d apart. The electric field at midpoint is:

(a) Zero (b) q/(2πε₀d²) towards -q (c) q/(πε₀d²) towards +q (d) 2q/(πε₀d²)

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Correct Answer: (b) q/(2πε₀d²) towards -q

Explanation:
Fields add up towards negative charge

4. The resistance of a wire is 4 Ω. If length is doubled and area halved, new resistance is:

(a) 4 Ω (b) 8 Ω (c) 16 Ω (d) 32 Ω

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Correct Answer: (c) 16 Ω

Explanation:
R ∝ L/A → new R = 4 × (2L)/(A/2) = 16 Ω

5. The time period of a satellite in low Earth orbit is approximately:

(a) 24 hours (b) 90 minutes (c) 12 hours (d) 1 hour

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Correct Answer: (b) 90 minutes

Explanation:
Low Earth orbit satellites have period around 90 minutes

6. A lens has power -2 D. It is:

(a) Convex lens (b) Concave lens (c) Plano-convex (d) None

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Correct Answer: (b) Concave lens

Explanation:
Negative power means diverging (concave) lens

7. In pure inductive circuit, current:

(a) Leads voltage by 90° (b) Lags voltage by 90° (c) In phase (d) Leads by 180°

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Correct Answer: (b) Lags voltage by 90°

Explanation:
In pure inductor, current lags voltage by π/2

8. The moderator used in nuclear reactor is:

(a) Graphite (b) Heavy water (c) Both (d) Uranium

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Correct Answer: (c) Both

Explanation:
Graphite and heavy water are common moderators

9. If momentum is increased by 50%, kinetic energy increases by:

(a) 50% (b) 100% (c) 125% (d) 225%

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Correct Answer: (c) 125%

Explanation:
p increased by 50% → 1.5 times. KE ∝ p² → (1.5)² = 2.25 → increase of 125%

10. The physical quantity whose dimensional formula is [MLT⁻²] is:

(a) Force (b) Energy (c) Pressure (d) Power

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Correct Answer: (a) Force

Explanation:
F = ma → [M][LT⁻²] = [MLT⁻²]