Online Exam on A.C. Fundamentals and Circuit Theory - Set 08

Practice Test: Question Set - 08


1. For the same peak value, which of the following wave has the least mean value?
    (A) Half wave rectified sine wave
    (B) Triangular wave
    (C) Sine wave
    (D) Square wave

2. The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that
    (A) Both waves must have same frequency
    (B) Both waves must have identical peak values
    (C) Both waves must have zero value at the same time
    (D) None of the above

3. The square waveform of current has following relation between r.m.s. value and average value.
    (A) r.m.s. value is equal to average value
    (B) r.m.s. value of current is greater than average value
    (C) r.m.s. value of current is less than average value
    (D) None of the above

4. Time constant of an inductive circuit
    (A) Increases with increase of inductance and decrease of resistance
    (B) Increases with the increase of inductance and the increase of resistance
    (C) Increases with the decrease of inductance and decrease of resistance
    (D) Increases with decrease of inductance and increase of resistance

5. In AC. circuits, laminated iron is invariably used in order to
    (A) Reduce eddy current loss
    (B) Increase heat radiation
    (C) Make assembly cheap and easier
    (D) Reduce circuit permeability

6. At __________ frequencies the parallel R-L circuit behaves as purely resistive.
    (A) Low
    (B) Very low
    (C) High
    (D) Very high

7. When an alternating current passes through an ohmic resistance the electrical power converted into heat is
    (A) Apparent power
    (B) True power
    (C) Reactive power
    (D) None of the above

8. Power factor of an electrical circuit is equal to
    (A) R/Z
    (B) Cosine of phase angle difference between current and voltage
    (C) Ratio of useful current to total current Iw/I
    (D) All above

9. In a purely inductive circuit
    (A) Actual power is zero
    (B) Reactive power is zero
    (C) Apparent power is zero
    (D) None of above is zero

10. Time constant of an inductive circuit
    (A) Increases with increase of inductance and decrease of resistance
    (B) Increases with the increase of inductance and the increase of resistance
    (C) Increases with decrease of inductance and decrease of resistance
    (D) Increases with decrease of inductance and increase of resistance

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