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 $....... \%$.

An electric heater is marked with $220\, V$ and $1100\, W$. If it is used for $4\, hours$, the energy consumed in $kWh$ will be:

When a current flows through a wire of resistance $R$ under a constant potential difference,the heat produced by the current is inversely proportional to:

$A$ resistor develops $500 \, J$ of thermal energy in $20 \, s$ when a current of $1.5 \, A$ is passed through it. If the current is increased from $1.5 \, A$ to $3 \, A$,what will be the energy (in $J$) developed in $20 \, s$?

Heating coils rated at $220\, V$ are available with resistances of $55\,\Omega$,$110\,\Omega$,$220\,\Omega$,and $440\,\Omega$. Which resistance value will produce the maximum power?

If the current in an electric bulb is changed by $1\%$,then the percentage change in power will be ............. $\%$.