Question

Resistances $R_{1}$ and $R_{2}$ are joined in parallel and a current is passed so that the amount of heat liberated is $H_{1}$ and $H_{2}$ respectively. The ratio $\frac{H_{1}}{H_{2}}$ has the value

• A. $\frac{R_{2}}{R_{1}}$
• B. $\frac{R_{1}}{R_{2}}$
• C. $\frac{R_{1}^{2}}{R_{2}^{2}}$
• D. $\frac{R_{2}^{2}}{R_{1}^{2}}$

Answer 1

Answer: (A)

$\frac{R_{2}}{R_{1}}$

Answer 2

Heat produced$H = \frac{V^{2}t}{4.2R} = H \propto \frac{1}{R}$

Hence $\frac{H_{1}}{H_{2}} = \frac{R_{2}}{R_{1}}$