MCQ Collection
ECAT MCQs
Practice ECAT questions with answers and explanations.
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Correct Answer: A. Splitting a heavy nucleus into lighter nuclei with energy release
Explanation:
Fission can release neutrons that sustain a chain reaction.
It powers conventional nuclear reactors.
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Correct Answer: B. Combining light nuclei to form a heavier nucleus with energy release
Explanation:
Fusion powers stars by converting a small amount of mass into energy.
It requires very high temperatures to overcome electric repulsion.
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Correct Answer: C. 3.315 × 10^-19 J
Explanation:
Photon energy is E=hf.
E=6.63×10^-34×5×10^14 = 3.315×10^-19 J.
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Correct Answer: D. 60 μC
Explanation:
Use Q=CV.
Q=5 μF×12 V = 60 μC.
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Correct Answer: D. 6.03 × 10^14 Hz
Explanation:
Frequency is f=E/h.
F=4.0×10^-19 / 6.63×10^-34 ≈ 6.03×10^14 Hz.
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Correct Answer: A. 24 N
Explanation:
Magnetic force is F=qvB for perpendicular motion.
F=2×3×4 = 24 N.
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Correct Answer: A. 3 eV
Explanation:
Einstein's photoelectric equation gives Kmax=Ephoton-φ.
Kmax=5-2 = 3 eV.
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Correct Answer: B. 6 N
Explanation:
Force on a current-carrying wire is F=BIL.
F=3×4×0.5 = 6 N.
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Correct Answer: B. 1 × 10^-10 m
Explanation:
Use λ=h/p.
λ=6.63×10^-34 / 6.63×10^-24 = 1×10^-10 m.
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Correct Answer: C. 4 V
Explanation:
Faraday's law gives emf=|ΔΦ/Δt| for one turn.
0.8/0.2 = 4 V.
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Correct Answer: C. 3 eV
Explanation:
The photon energy equals the difference between levels.
E=5-2 = 3 eV.
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Correct Answer: D. 100 V
Explanation:
Voltage ratio equals turns ratio.
Vs=20×500/100 = 100 V.
