Calculate the number of electrons that would flow per second through the cross-section of a wire when $1 \, A$ current flows in it.

$A$ wire of length $L$ and resistance $R$ is stretched so that the length is doubled and area of cross-section is halved. How will its
$(a)$ resistance change?
$(b)$ resistivity change?

An electric heater draws a current of $2\;A$ when connected to a voltage source of $120\;V$. What is the resistance of the heater coil?

The voltage-current variation of two metallic wires $X$ and $Y$ at constant temperature are shown below. Assuming that the wires have the same length and the same diameter, explain which of the two wires will have larger resistivity.

The potential difference between the terminals of an electric heater is $60\, V$ when it draws a current of $4\, A$ from the source. What current will the heater draw,if the potential difference is increased to $120\, V$ (in $, A$)?

$1 \text{ kWh} = 3.6 \times 10^6 \text{ joules}$. Is this statement true or false?