A water heater is marked 1500W, 220V. If the voltage drops to 180V,calculate the power consumed by the heater.

P₁=V₁I, 1500=220*I Hence I=150/22..............................(1)

P₂= V₂i P₂=180*150/22 from (1)

Hence P₂ =1227.27 W

(or)

P₁=V₁I, P₁=V₁²/R..................(1)

P₂=V₂I,P₂=V₂²/R....................(2)

P₁/P₂=V₁² / V₂²

P₂=P₁*V₂²/V₁²

P₂=1500*(180)2/(220)2

P₂=1004.13W

WHICH OF THE ABOVE METHODS ARE CORRECT AND WHY?? CAN U PLEASE EXPLAIN???

Amit Saxena , 11 Years ago

Grade upto college level