A.C Fundamentals Multiple Choice Questions - Set 02 - ObjectiveBooks

# Practice Test: Question Set - 02

1. The power is measured in terms of decibels in case of
(A) Electronic equipment
(B) Transformers
(C) Current transformers
(D) Auto transformers

2. Wire-wound resistors are unsuitable for use at high frequencies because they
(A) Create more electrical noise
(B) Are likely to melt under excessive eddy current heat
(C) Consume more power
(D) Exhibit unwanted inductive and capacitive effects

3. The product of apparent power and cosine of the phase angle between circuit voltage and current is
(A) True power
(B) Reactive power
(C) Volt-amperes
(D) Instantaneous power

4. In a series resonant circuit, the impedance of the circuit is
(A) Minimum
(B) Maximum
(C) Zero
(D) None of the above

5. In series resonant circuit, increasing inductance to its twice value and reducing capacitance to its half value
(A) Will change the maximum value of current at resonance
(B) Will change the resonance frequency
(C) Will change the impedance at resonance frequency
(D) Will increase the selectivity of the circuit

6. In a loss-free R-L-C circuit the transient current is
(A) Oscillating
(B) Square wave
(C) Sinusoidal
(D) Non-oscillating

7. In a circuit containing R, L and C, power loss can take place in
(A) C only
(B) L only
(C) R only
(D) All above

8. Time constant of a capacitive circuit
(A) Increases with the decrease of capacitance and decrease of resistance
(B) Increases with the decrease of capacitance and increase of resistance
(C) Increases with the increase of capacitance and decrease of resistance
(D) Increase with increase of capacitance and increase of resistance

9. The effective resistance of an iron-cored choke working on ordinary supply frequency is more than its true resistance because of
(A) Iron loss in core
(B) Skin effect
(C) Increase in temperature
(D) Capacitive effect between adjacent coil turns

10. Skin effect occurs when a conductor carries current at _________ frequencies.
(A) Very low
(B) Low
(C) Medium
(D) High

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