$Ohm's$ law is a relation between the power used in a circuit to the current and the potential difference.

Define $1$ volt.

What will happen to the current flowing through a conductor,if the potential difference is doubled?

$(a)$ What do the following symbols represent in a circuit? Write the name and one function of each.
$(b)$ Draw a schematic diagram of a circuit consisting of a battery of $12 \, V$,three resistors of $5 \, \Omega$,$10 \, \Omega$,and $20 \, \Omega$ connected in parallel,an ammeter to measure the total current through the circuit,and a voltmeter to measure the potential difference across the combination of resistors.
$(c)$ State any one advantage of connecting electrical devices in parallel with the mains instead of connecting them in series in a household circuit.

Derive an expression for equivalent resistance when three resistors of resistance $R_{1}, R_{2}$ and $R_{3}$ are connected in parallel.

$A$ series circuit has only one conducting path for the electrons that move through it; a parallel circuit has multiple conducting paths.