$A$ battery is a source of maintaining a constant potential difference across two ends of a conductor.

If the diameter of a conducting wire is doubled,how many times does its resistance become?

Draw a schematic diagram of a circuit consisting of a cell of $1.5 \, V$, a $10 \, \Omega$ resistor, a $15 \, \Omega$ resistor, and a plug key, all connected in series.

Which one of the following is true according to Ohm's law?

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

$(i)$ Draw a circuit diagram to show how two resistors are connected in series.
$(ii)$ In a circuit,if two resistors of $5 \ \Omega$ and $10 \ \Omega$ are connected in series,how does the current passing through the two resistors compare?