Question

A bulb is rated as 250 V; 0.4 A. Find its : (i) power, and (ii) resistance.

Answer 1

Given:
              V = 250 V
               I = 0.4 A

Power, P = VI
               = 250 x 0.4
               = 100 W
 
Resistance, R = `R=P/(I2) `

                    = `100/(0.4)^2`       
                  = 625 Ω