(a(i))[4]
Describe two ways in which boiling and evaporation differ.
(a(ii))[2]
Explain, in molecular terms, why thermal energy must be supplied in order to boil a liquid.
(b(i))[2]
Calculate the mass of water discharged from the shower in $1.0\,\text{s}$.
(b(ii))[3]
Calculate the thermal energy gained by the water in $1.0\,\text{s}$.
(b(iii))[2]
To work out the shower’s efficiency, you need the value from (b)(ii) and one other quantity. 1. State what that other quantity is. 2. Describe how the two values are combined to calculate the shower’s efficiency.
(b(iv))[2]
The electric heater is housed in a metal pipe that is earthed. Explain why this is needed.