Munish's room heater is marked as 2000 W - 200 V. Find the percentage | inte, change in the power of heater if voltage a pa drops to 180 V.

Explanation

Case I :
P = 2000 W
V = 200 V
`R = V^2/P = (200xx200)/2000=20Omega`
Case - II : `R = 20 Omega`
V. = 180 V
P. = ?
`P.=((V.)^2)/R=(180xx180)/(20)`
P. = 1720 W
Percentage change in power
`= (P-P.)/Pxx100`
`= (200-1720)/(2000) xx 100 = 14%`