NEET UG PHYSICS Multiple Choice Questions (MCQs)
NEET UG Physics - Unit 14: Electromagnetic Induction and Alternating Currents
NEET UG Physics - Unit 14: Electromagnetic Induction and Alternating Currents
196. What does Faraday's Law of Electromagnetic Induction state?
a) The induced emf is directly proportional to the rate of change of magnetic flux.
b) The induced emf is inversely proportional to the rate of change of magnetic flux.
c) The induced current is independent of the rate of change of magnetic flux.
d) The induced emf is independent of the area of the loop.
Answer: a) The induced emf is directly proportional to the rate of change of magnetic flux.
197. According to Lenz's Law, the direction of induced current is such that it:
a) Opposes the change in magnetic flux that produced it.
b) Aims to increase the magnetic flux through the coil.
c) Does not affect the magnetic flux.
d) Supports the change in magnetic flux.
Answer: a) Opposes the change in magnetic flux that produced it.
198. Eddy currents are caused by:
a) A constant magnetic field.
b) A time-varying magnetic field.
c) A static electric field.
d) A constant electric field.
Answer: b) A time-varying magnetic field.
199. Self-inductance is the property of a coil that resists changes in:
a) Current in the coil.
b) Voltage across the coil.
c) Magnetic field strength.
d) Electric field in the coil.
Answer: a) Current in the coil.
200. Mutual inductance occurs when:
a) The current in one coil induces a current in the same coil.
b) The current in one coil induces a current in another coil.
c) There is no current in any coil.
d) The current in one coil is constant.
Answer: b) The current in one coil induces a current in another coil.
201. The RMS value of an alternating current is:
a) The maximum value of the current.
b) The average value of the current over one cycle.
c) The value of the current that produces the same heating effect as a DC current.
d) The peak value of the current divided by \(\sqrt{2}\).
Answer: c) The value of the current that produces the same heating effect as a DC current.
202. The peak value of an alternating current is:
a) \( I_{\text{peak}} = I_{\text{RMS}} \).
b) \( I_{\text{peak}} = \sqrt{2} \times I_{\text{RMS}} \).
c) \( I_{\text{peak}} = I_{\text{RMS}} / \sqrt{2} \).
d) \( I_{\text{peak}} = I_{\text{RMS}}^2 \).
Answer: b) \( I_{\text{peak}} = \sqrt{2} \times I_{\text{RMS}} \).
203. The reactance of an inductor is given by:
a) \( X_L = \frac{1}{\omega L} \).
b) \( X_L = \omega L \).
c) \( X_L = \frac{1}{L} \).
d) \( X_L = L \).
Answer: b) \( X_L = \omega L \).
204. In an LCR series circuit, resonance occurs when:
a) The impedance is minimum.
b) The current is maximum.
c) The voltage across the inductor is zero.
d) The phase difference is 90°.
Answer: a) The impedance is minimum.
205. The power in an AC circuit with a resistive load is maximum when:
a) The frequency is zero.
b) The current is at its RMS value.
c) The voltage is at its peak value.
d) The phase difference between current and voltage is 0°.
Answer: d) The phase difference between current and voltage is 0°.
206. The expression for impedance in an LCR series circuit is:
a) \( Z = \sqrt{R^2 + X_L^2} \).
b) \( Z = \sqrt{R^2 + X_C^2} \).
c) \( Z = R + X_L + X_C \).
d) \( Z = \sqrt{R^2 + (X_L - X_C)^2} \).
Answer: d) \( Z = \sqrt{R^2 + (X_L - X_C)^2} \).
207. In an AC circuit, a wattless current refers to:
a) A current that does not produce any power.
b) A current that produces maximum power.
c) A current that produces a zero average power over a cycle.
d) A current that only passes through the inductor.
Answer: c) A current that produces a zero average power over a cycle.
208. An AC generator works on the principle of:
a) Electromagnetic induction.
b) Magnetic force on a moving charge.
c) Ampere's law.
d) Coulomb's law.
Answer: a) Electromagnetic induction.
209. The frequency of an AC supply is measured in:
a) Hertz (Hz).
b) Ampere (A).
c) Ohms (Ω).
d) Watts (W).
Answer: a) Hertz (Hz).
210. The power factor of an AC circuit is the ratio of:
a) The average power to the maximum power.
b) The current to the voltage.
c) The voltage to the current.
d) The real power to the apparent power.
Answer: d) The real power to the apparent power.
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