MCQ Collection
ECAT MCQs
Practice ECAT questions with answers and explanations.
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Correct Answer: A. 6000 J
Explanation:
Energy is E=Pt.
E=100×60 = 6000 J.
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Correct Answer: B. Magnetic field passing through an area
Explanation:
For a uniform field, flux is BA cosθ.
Its SI unit is the weber.
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Correct Answer: B. 36 W
Explanation:
Use P=I²R.
P=3²×4 = 36 W.
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Correct Answer: C. Current that changes magnitude and direction periodically
Explanation:
AC reverses direction with time.
Mains electricity is commonly sinusoidal alternating current.
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Correct Answer: C. 2 μF
Explanation:
Capacitance is C=Q/V.
C=20 μC/10 V = 2 μF.
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Correct Answer: D. A device that changes AC voltage using electromagnetic induction
Explanation:
Transformers use changing magnetic flux in coupled coils.
They ideally conserve power while changing voltage and current.
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Correct Answer: A. 0.054 N
Explanation:
Use F=kq1q2/r² with charges in coulombs.
F=9×10^9×2×10^-6×3×10^-6 = 0.054 N.
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Correct Answer: B. It becomes one-ninth
Explanation:
Coulomb force varies inversely with distance squared.
Tripling distance multiplies force by 1/3² = 1/9.
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Correct Answer: C. 5 N/C
Explanation:
Electric field is force per unit charge.
E=20/4 = 5 N/C.
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Correct Answer: D. 24 J
Explanation:
Electrical work is W=QV.
W=2×12 = 24 J.
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Correct Answer: A. -2 D
Explanation:
Power is P=1/f.
P=1/(-0.50) = -2 D.
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Correct Answer: A. Their resistances add directly
Explanation:
Series resistors carry the same current.
The voltage drops add to the source voltage.
