Define $1$ volt.

Why is much less heat generated in long electric cables than in filaments of electric bulbs?

If a $12 \ V$ battery is connected to the arrangement of resistances given below,calculate
$(i)$ the total effective resistance of the arrangement and
$(ii)$ the total current flowing in the circuit.

Define resistivity of a material.

How are electrical appliances connected to the main line in our homes?

Draw a circuit diagram for a circuit consisting of a battery of five cells of $2 \text{ V}$ 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
$(ii)$ the potential difference across the $5 \, \Omega$ resistor when the key is closed.