# 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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