Which of the following graphs correctly represents the variation of heat energy $(U)$ produced in a metallic conductor in a given time as a function of potential difference $(V)$ across the conductor?

Two bulbs are rated $(40 \; W, 200 \; V)$ and $(100 \; W, 200 \; V)$. What is the correct relation for their resistances?

$A$ light bulb operates at a voltage $V_0$ and consumes power $P_0$. If the voltage is changed to $V$,what is the new power $P$ consumed by the bulb?

$A$ bulb has a specification of $1\, kW$ and $250\, V$. The resistance of the bulb is .................. $\Omega$.

$A$ 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 $..... \, J$.

$A$ house is served by a $220 \, V$ supply line in a circuit protected by a $9 \, A$ fuse. What is the maximum number of $60 \, W$ lamps in parallel that can be turned on simultaneously?