#### Question :

A student boils the water in an electric kettle for 20 minutes after being switched on. If the boiling time is to be decreased then what should be the length of the heating element ?Submitted on 10/2/2024 | Answered by Vandana Rana#### Answer :

The student should decrease the length of the heating element to decrease the boiling time.By Ohm’s law of heating, the heat produced is given as

H=I²Rt

But it is known that the current is given as

I = V/R

Hence the equation for the heat produced can also be written as

H = V²tR

Since, the heat required is the same in both cases, it can be stated that

V²t1R1=V²t2R2 or it can be written as t1/t2=R2/R1 From the above relation, for t2 to be less than t1, R2 should be lesser than R1 if we want the water to boil quicker.