The distllled water acts as ........ for the electricity.

A potential difference $V$ is applied across a conductor of length $L$ and diameter $D .$ How is the resistance $R$ of the conductor affected, when in turn $(i)$ $V$ is halved $(ii)$ $L$ is halved and $(iii)$ $D$ is doubled ? Justify your answer in each case.

Draw a circuit diagram for a circuit consisting of a battery of five cells of $2$ volts each, a $5\, \Omega,$ resistor, a $10\, \Omega$ resistor and a $15 \,\Omega$ resistor, an ammeter and a plug key; all connected in series. Also, connect a voltmeter to record the potential difference across the $15\, \Omega$ resistor and calculate

$(i)$ the electric current passing through the above circuit and

$(ii)$ potential difference across $5\, \Omega$ resistor when the key is closed.

The $V-I$ graphs for two resistors of the same material and the same radii with lengths $L_{1}$ and $L_{2}$ are shown below. If $L_{1}>L_{2}$, state with reason, which of these graphs represents voltage-current change for $L_{1}$.

What is the unit of electric current?

The formula for an electric current is $.....$