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
$\frac{{{R_2}}}{{{R_1}}}$
$\frac{{{R_1}}}{{{R_2}}}$
$\frac{{R_1^2}}{{R_2^2}}$
$\frac{{R_2^2}}{{R_1^2}}$
Two bulbs $X$ and $Y$ having same voltage rating and of power $40\, watt$ and $60\, watt$ respectively are connected in series across a potential difference of $300\, volt$, then
A $25\, watt$, $220\, volt$ bulb and a $100\, watt$, $220\, volt$ bulb are connected in series across a $220\, volt$ lines. Which electric bulb will glow more brightly
The circuit below is used to heat water kept in a bucket. Assuming heat loss only by Newton's law of cooling, the variation in the temperature of the water in the bucket as a function of time is depicted by
A wire of length $L$ and $3$ identical cells of negligible internal resistances are connected in series. Due to current, the temperature of the wire is raised by $\Delta T$ in a time $t$. A number $N$ of similar cells is now connected in series with a wire of the same material and cross-section but of length $2\, L$. The temperature of the wire is raised by the same amount $\Delta T$ in the same time $t$. the value of $N$ is
Two light bulbs in the circuit have rating $A\,[24\ V, 48\,W]$ and $B\,[24\ V, 36\,W]$ as shown.