Practice Test: Question Set - 06
1. In a series L-C circuit at the resonant frequency the
- (A) Current is maximum
- (B) Current is minimum
- (C) Impedance is maximum
- (D) Voltage across C is minimum
2. A pure inductance connected across 250 V, 50 Hz supply consumes 100 W. This consumption can be attributed to
- (A) The big size of the inductor
- (B) The reactance of the inductor
- (C) The current flowing in the inductor
- (D) The statement given is false
3. In a parallel R-C circuit, the current always _________the applied voltage
- (A) Lags
- (B) Leads
- (C) Remains in phase with
- (D) None of the above
4. In a three-phase supply floating neutral is undesirable because it way give rise to
- (A) High voltage across the load
- (B) Low voltage across the load
- (C) Unequal line voltages across the load
- (D) None of these
5. An A.C. voltage is impressed across a pure resistance of 3.5 ohms in parallel with a pure inductance of impedance of 3.5 ohms,
- (A) The current through the resistance is more
- (B) The current through the resistance is less
- (C) Both resistance and inductance carry equal currents
- (D) None of the above
6. Inductance affects the direct current flow
- (A) Only at the time of turning off
- (B) Only at the time of turning on
- (C) At the time of turning on and off
- (D) At all the time of operation
7. The time constant of the capacitance circuit is defined as the time during which voltage
- (A) Falls to 36.8% of its final steady value
- (B) Rises to 38.6% of its final steady value
- (C) Rises to 63.2% of its final steady value
- (D) None of the above
8. Power factor of electric bulb is
- (A) Zero
- (B) Lagging
- (C) Leading
- (D) Unity
9. If a sinusoidal wave has frequency of 50 Hz with 30 A r.m.s. current which of the following equation represents this wave?
- (A) 42.42 sin 314 t
- (B) 60 sin 25 t
- (C) 30 sin 50 t
- (D) 84.84 sin 25 t
10. Capacitive susceptance is a measure of
- (A) Reactive power in a circuit
- (B) The extent of neutralization of reactive
power in a circuit
- (C) A purely capacitive circuit's ability to
pass current
- (D) A purely capacitive circuit's ability to
resist the flow of current
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