A power station supplies electrical energy to the grid at a voltage of $25\mathrm{kV}$. Calculate the output power of the station when the current it supplies is $40\mathrm{kA}$.

An energy-efficient light bulb is labelled $\text{'}230 \mathrm{V},15 \mathrm{W}\text{'}$. This means that when connected to the $230 \mathrm{V}$ mains supply it is fully lit and changes electrical energy to heat and light at the rate of $15 \mathrm{W}$. Calculate the current in the bulb when fully lit.

An energy-efficient light bulb is labelled $\text{'}230 \mathrm{V},15 \mathrm{W}\text{'}$. This means that when connected to the $230 \mathrm{V}$ mains supply it is fully lit and changes electrical energy to heat and light at the rate of $15 \mathrm{W}$. Calculate:

(b) Its resistance when fully lit.

A $12 \mathrm{V}$ car battery can supply a current of $10 \mathrm{A}$ for $5.0$ hours. Calculate how many joules of energy the battery transfers in this time.

A lamp is operated for $20 \mathrm{s}$. The current in the lamp is $10 \mathrm{A}$. In this time, it transfers $400 \mathrm{J}$ of energy to the lamp. Calculate:

(a) How much charge flows through the lamp.

A lamp is operated for $20 \mathrm{s}$. The current in the lamp is $10 \mathrm{A}$. In this time, it transfers $400 \mathrm{J}$ of energy to the lamp. Calculate:

(b) How much energy each coulomb of charge transfers to the lamp

A lamp is operated for $20 \mathrm{s}$. The current in the lamp is $10 \mathrm{A}$. In this time, it transfers $400 \mathrm{J}$ of energy to the lamp. Calculate:

(c) The p.d. across the lamp.