Sat February 21, 2009 By: Shryans Baid

Water Heat

Expert Reply
Sun February 22, 2009

In both the cases the heat supplied by the electric kettle will be same. Also since the same kettle is used, the resistance(R) will be same in both the cases.

Let,  V1= 220 v , t1 = 5 min and V2 = 200 v, t2 = ?

using the formula below, the required time can be calculated.

(V12t1)/R = (V22 t2)/ R

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