Alternating Current MCQs for MDCAT Practice

Physics section, Alternating Current chapter. Sample questions from past PMC papers.

1. Question 1
   An alternating voltage V (in volts) is represented by the equation:V = 300 sin(100πt) What is the value of “f” for this voltage?
   • A.100 Hz
   • B.50 Hz
   • C.25 H
   • D.200 Hz
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2. Question 2
   what is the quality factor of resistance?
   • A.Zero
   • B.∞
   • C.Infinite
   • D.Maximum but finite
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3. Question 3
   The power factor of a purely capacitive circuit is:
   • A.0
   • B.1
   • C.infinite
   • D.0.5
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4. Question 4
   A heater marked 1000 W, 250 V is connected to a 220 V(rms) AC supply. Assuming it's purely resistive, calculate the actual power it consumes.
   • A.880W
   • B.774.4W
   • C.950W
   • D.1000W
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5. Question 5
   The effective value of alternating current is:
   • A.√2 times its maximum value
   • B.1√2 times its maximum value
   • C.2 times its maximum value
   • D.1/2 times its maximum value
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6. Question 6
   The electromagnetic radiations are in descending order of wavelength in the following sequence:
   • A.Infra-red waves, radio waves, X-rays, visible light rays
   • B.Radio-waves, infra-red waves, visible light rays, X-rays
   • C.Radio waves, visible light rays, infra-red waves, X-rays
   • D.X-rays, visible light rays, infra-red wave, Radio-waves
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7. Question 7
   How many times per second will an incandescent lamp reach maximum brilliances when connected to a 50Hz source?
   • A.25 times
   • B.50 times
   • C.100 times
   • D.200 times
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8. Question 8
   Describe impedance as vector sum of resistances and reactances.
   • A.Impedance is the algebraic sum of resistance and reactance.
   • B.Impedance is the vector sum of resistance and reactance.
   • C.Impedance is the scalar sum of resistance and reactance.
   • D.Impedance is the arithmetic sum of resistance and reactance.
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