Question

A fully charged capacitor has a capacitance C. It is discharged through a small coil of resistance wire embedded in a thermally insulated block of specific heat capacity s and mass m. If the temperature of the block is raised by $T$, the potential difference V across the capacitance is

• A. $\frac{msT}{C}$
• B. $\sqrt{\frac{2msT}{C}}$
• C. $\sqrt{\frac{2mCT}{s}}$
• D. $\frac{mCT}{s}$

Answer 1

The correct option is B $\sqrt{\frac{2msT}{C}}$

Energy stored in a capacitor $u=\frac{1}{2}c{v}^2$
$\frac{1}{2}c{v}^2=ms\Delta T$
$\Rightarrow v=\sqrt{\frac{2ms\Delta T}{c}}$