Question

A bulb of rated values 60 V, 10 W is connected in series with a source of 100 V and 50 Hz. The coefficient of self induction of a coil to be connected in series for its operation will be

• A. 1.53 H
• B. 2.15 H
• C. 3.27 H
• D. 3.89 H

Answer 1

Answer: (A)

1.53 H

Answer 2

I_bulb = $\frac { 10 } { 60 }$ = $\frac { 1 } { 6 }$A = I_L

V_L = $\sqrt { 100 ^ { 2 } - 60 ^ { 2 } }$= 80 volt

Ž I X_L = 80 Ž I (2p fL) = 80

Ž $\frac { 1 } { 6 }$ (2p × 50 × L) = 80 Ž L = 1.53 H