$A$ room heater is rated $400 \text{ W}$, $220 \text{ V}$. If the supply voltage drops to $200 \text{ V}$, what will be the power consumed (approximately) (in $\text{ W}$)?

The maximum current that flows through a fuse wire before it blows out varies with its radius as

An electric bulb is designed to draw power $P_0$ at voltage $V_0$. If the voltage is $V$,it draws a power $P$. Then:

If a wire of resistance $20\,\Omega$ is covered with ice and a voltage of $210\,V$ is applied across the wire,then the rate of melting of ice is .................. $g/s$. (Take latent heat of fusion of ice $L = 80\,cal/g$ and $1\,cal = 4.2\,J$)

$A$ wire of resistance $R$ is connected across a cell of emf $\varepsilon$ and internal resistance $r$. The current through the circuit is $I$. In time $t$,the work done by the battery to establish the current $I$ is

$A$ resistor dissipates $192 \, J$ of energy in $1 \, s$ when a current of $4 \, A$ is passed through it. Now,when the current is doubled,the amount of thermal energy dissipated in $5 \, s$ is $..... \, J$.