State $Ohm's$ law. Calculate the resistance of a conductor,if the current flowing through it is $0.2 \, A$ when the applied potential difference is $0.8 \, V$.

$(a)$ Define potential difference between two points in a conductor.
$(b)$ Name the instrument used to measure the potential difference in a circuit. How is it connected?
$(c)$ $A$ current of $2 \, A$ passes through a circuit for $1$ minute. If the potential difference between the terminals of the circuit is $3 \, V$, what is the work done in transferring the charges?

An electric kettle consumes $1\, kW$ of electric power when operated at $220\, V$. $A$ fuse wire of what rating (in $A$) must be used for it?

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

Give a single word for $\frac{1 \text{ joule}}{1 \text{ coulomb}}$.

Electric power is also called $BOTU$.