An electrical power line, having a total resistance of $2 \, \Omega$, delivers $1 \, kW$ at $220 \, V$. The efficiency of the transmission line is approximately $....... \%$.

Two electric bulbs whose resistances are in the ratio of $1:2$ are connected in series. The powers dissipated in them have the ratio:

In a $Ag$ voltameter,$2.68 \, g$ of silver is deposited in $10 \, \min$. The heat developed in a $20 \, \Omega$ resistor during the same period will be:

Two heating coils of resistances $10 \Omega$ and $20 \Omega$ are connected in parallel and connected to a battery of emf $12 \text{ V}$ and internal resistance $1 \Omega$. The ratio of the power consumed by them is:

$A$ $12 \text{ HP}$ motor has to be operated $8 \text{ hours/day}$. How much will it cost at the rate of $50 \text{ paisa/kWh}$ in $10$ days? (in $Rs.$)

$A$ current of $2\, mA$ was passed through an unknown resistor which dissipated a power of $4.4\, W$. The dissipated power when an ideal power supply of $11\, V$ is connected across it is: