question_answer

In the circuit shown, the resistance r is a variable resistance. If for \[r=fR,\] the heat generation in r is maximum then the value of f is:               [JEE ONLINE 09-04-2016]

A) 1

B) \[\frac{3}{4}\]

C) \[\frac{1}{4}\]

D) \[\frac{1}{2}\]

Correct Answer: D

Solution :

[d]

to get maximum heat generation from r.

\[r={{\operatorname{R}}_{eq}}=R/2\]