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Physics MCQ Practice 13 — Science Foundation Course for Class 11 & 12
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1.
A body starts from rest and covers 100 m in 5 seconds with uniform acceleration. The acceleration is:
(a) 4 m/s²
(b) 8 m/s²
(c) 10 m/s²
(d) 2 m/s²
Show Answer & Explanation
Correct Answer: (b) 8 m/s²
Explanation:
s = ½at² → 100 = ½a×25 → a = 8 m/s²
2.
The ratio of gravitational force on Earth to Moon is 6:1. The ratio of their radii is approximately:
(a) 6:1
(b) 3.7:1
(c) 1:6
(d) 2:1
Show Answer & Explanation
Correct Answer: (b) 3.7:1
Explanation:
g ∝ M/R ² → ratio leads to R_E / R_M ≈ 3.7
3.
Three capacitors 2 μF, 4 μF and 6 μF in series. Equivalent capacitance is:
(a) 12 μF
(b) 1.09 μF
(c) 3 μF
(d) 0.92 μF
Show Answer & Explanation
Correct Answer: (b) 1.09 μF
Explanation:
1/C = 1/2 + 1/4 + 1/6 ≈ 0.9167 → C ≈ 1.09 μF
4.
The beat frequency produced by two tuning forks of 256 Hz and 260 Hz is:
(a) 4 Hz
(b) 8 Hz
(c) 516 Hz
(d) 0 Hz
Show Answer & Explanation
Correct Answer: (a) 4 Hz
Explanation:
Beat frequency = |f₁ - f₂| = 4 Hz
5.
The force on a charged particle moving perpendicular to magnetic field is maximum when angle is:
(a) 0°
(b) 45°
(c) 90°
(d) 180°
Show Answer & Explanation
Correct Answer: (c) 90°
Explanation:
F = qvB sinθ → maximum at 90°
6.
A convex mirror has focal length 30 cm. For an object at 20 cm, image distance is:
(a) 60 cm
(b) 12 cm
(c) -12 cm
(d) 15 cm
Show Answer & Explanation
Correct Answer: (b) 12 cm
Explanation:
1/v + 1/u = 1/f (convex positive f) → v = +12 cm (virtual)
7.
In a series RLC circuit at resonance, the current is:
(a) Minimum
(b) Maximum
(c) Zero
(d) Infinite
Show Answer & Explanation
Correct Answer: (b) Maximum
Explanation:
Impedance minimum (=R) at resonance → current maximum
8.
The phenomenon of splitting of white light into colours is called:
(a) Reflection
(b) Refraction
(c) Dispersion
(d) Diffraction
Show Answer & Explanation
Correct Answer: (c) Dispersion
Explanation:
Dispersion is splitting of light into spectrum
9.
If the amplitude of a wave is doubled, its energy becomes:
(a) Same
(b) Double
(c) Four times
(d) Half
Show Answer & Explanation
Correct Answer: (c) Four times
Explanation:
Energy ∝ (amplitude)²
10.
The dimensional formula of angular velocity is:
(a) [T⁻¹]
(b) [MLT⁻¹]
(c) [M⁰L⁰T⁻¹]
(d) [M⁻¹L²T⁻¹]
Show Answer & Explanation
Correct Answer: (c) [M⁰L⁰T⁻¹]
Explanation:
ω = θ/t → [T⁻¹]