Calculate the curren and the resistance of a 100W, 200V electric bulb in an electric circuit.

Explanation

(a) Given, P=100W, V=200V
Power, P=V I
So, Current, I=`(P)/(V)`
`=(100)/(20)=0.5`
Resistance, R=`(V)/(I)`
`=(200)/(0.5)=400Omega`
(b) (i) The earth wire provides a low resistance path to the electric current.
(ii) The earth wire sends the current from the body of the appliance to the Earth, whenever a live wire accidentally touches the body of the metallic electric appliance.
(iii) Thus, the earth wire serves as a protective conductor, which saves us from electric shocks.