A 60V, 10W lamp is to be run on 100V,60Hz ac mains. Calculate the inductance of a choke coil require to be connected in series with it to work the bulb.

Given: For a lamp V=60V P=10W V rms 100 v 1. Resistance of the lamp R R=V^2/p 60×60/10 =360 ohm 2 current I rms =p/v =10/60 =1/6A 3.impendance Z=V rms /I rms = 100/1/6 =600 ohm 4.inductance Z= under root R^2 +Xl^2 I OMEGA^2 =Z^2-R^2 L= UNER ROOT Z^2-R^2/OMEGA UNDER ROOT 600^2-360^2/2*3.14*60 (DENOMINATOR OUT OF ROOT ) =1.273H