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$\frac{{R_2^2}}{{R_1^2}}$
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A$\frac{{{R_2}}}{{{R_1}}}$
a (a) Heat produced $H = \frac{{{V^2}t}}{{4.2R}} = H \propto \frac{1}{R}$ Hence $\frac{{{H_1}}}{{{H_2}}} = \frac{{{R_2}}}{{{R_1}}}$
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