question_answer

Maximum power developed across variable resistance R in the circuit shown in the figure is

A)  50 watt                      

B)  75 watt

C)  25 watt                      

D)  100 watt

Correct Answer: A

Solution :

The given current can be redrawn as follows: Here, \[r=\frac{{{r}_{1}}{{r}_{2}}}{{{r}_{1}}+{{r}_{2}}}=\frac{1.1}{1+1}=\frac{1}{2}\Omega \] And \[E=\frac{\sum{E/r}}{\sum{1/r}}=\frac{\left( \frac{10}{1} \right)+\left( \frac{10}{1} \right)}{1+1}=10\,V\] Maximum power will be developed across R when \[R=r=\frac{1}{2}\Omega \] \[\therefore \]    \[{{i}_{\max }}=\frac{E}{r+R}=\frac{10}{\frac{1}{2}+\frac{1}{2}}=10A\] Hence, the correction option is [a].