Question

In the circuit shown (fig), X is joined to Y for a long time and then X is joined to Z. The total heat produced in $R_2$ is

• A. $\frac{L{E}^2}{2R_1^2}$
• B. $\frac{L{E}^2}{2R_2^2}$
• C. $\frac{L{E}^2}{2R_1{R}_2}$
• D. $\frac{L{E}^2{R}_2}{2R_1^3}$

Answer 1

The correct option is A $\frac{L{E}^2}{2R_1^2}$

The current in L for steady state $=\frac{E}{R_1}$
$\therefore$ Energy stored in $L=\frac{1}{2}L{I}_0^2=\frac{1}{2}L\frac{E^2}{R_1^2}$
This is equal to the heat produced in $R_2$ during discharge.