Page 420 - Basic Electrical Engineering

d. .

4. The impedance of a circuit is ∠30° The value of resistance and inductive reactance of the
circuit, respectively, are

a. 10 Ω and 17.32 Ω
b. 17.32 Ω and 10 Ω
c. 10 Ω and 10 Ω
d. 10 Ω and 8.66 Ω.

5. The impedance q an R–L series circuit is 628 ∠30° when the supply frequency is 50 Hz. The
value of inductance, L is

a. 314 H
b. 1 H
c. 2 H
d. 628 H.

6. An impedance of z = 6 + j8 Ω is connected across a 200 V, 50 Hz supply. The power factor of
the circuit is

a. 0.6 lagging
b. 0.6 leading
c. 0.75 lagging
d. 0.8 lagging.

7. The current flowing through the circuit of question 6 is

a. 10 A
b. 20 A
c. 14–28 A
d. 2 A.

8. An R–L series circuit has an impedance of 10 + j10 W. The power factor angle of the circuit is

a. 30° lagging
b. 30° leading
c. 45° leading
d. 45° lagging.

9. An R–C series circuit has a resistance of 10 Ω and a capacitive reactance of 10 Ω. What will
be the phase difference between the voltage and current in the circuit?

a. Current will lead the voltage by 90°
b. Current will lag the voltage by 90°
c. Current will lead the voltage by 45°