Jagriti's room heater is marked as 1500 W-250 V. Find the percentage in the power of heater if voltage drops to 160 volt.

Explanation

Case I :
P = 1500 W
V = 250 V
`R=(V^2)/P = (250xx250)/1500`
`R = 41.67Omega`
`V. = 160 V`
P. = ?
`P. = ((V.)^2)/R= (160xx160)/(41.67) =614.35W`
Percentage change in power `= (P-P.)/Pxx100`
`= (1500-614.35)/(1500) xx100 = 59.04%`