If the current passing through a heater is halved, then the heat produced by it becomes
2H
4H
H/2
H/4
The correct option is D. H/4
We know that,
H = I2 R t,
If Inew = I/2, then
Hnew = (I/2)2 R t
Hnew = (1/4) I2 R t = H/4.