A typical light dimmer used to dim the stage lights in a theatre consists of a variable induction for L (where inductance is adjustable between zero and\[{{L}_{\max }}\] connected in series with a light bulb B as shown. The mains electrical supply is 220 V a 50 Hz, the light bulb is rated at 220 V, 1100 W. What \[{{L}_{\max }}\]is required if the rate of energy dissipation in to mains the light bulb is to be varied by a factor of 5 from its upper limit of 1100W?

A typical light dimmer used to dim the stage lights in a theatre consi

1.	A typical light dimmer used to dim the stage lights in a theatre consists of a variable induction for L (where inductance is adjustable between zero and\[{{L}_{\max }}\] connected in series with a light bulb B as shown. The mains electrical supply is 220 V a 50 Hz, the light bulb is rated at 220 V, 1100 W. What \[{{L}_{\max }}\]is required if the rate of energy dissipation in to mains the light bulb is to be varied by a factor of 5 from its upper limit of 1100W?
A.	0.69 H
B.	0.28 H
C.	0.38 H
D.	0.56 H
Answer» C. 0.38 H