(a)[2]
State two energy resources whose main source of energy is radiation from the Sun.
(b(i))[2]
Show that the mass of air striking the turbine each second is about $550\,\text{kg}$.
(b(ii))[2]
Calculate the efficiency of the turbines. You may assume that all the kinetic energy in the wind is transferred to the turbine.
(c)[1]
Suggest one reason that tidal energy is a more useful energy resource than wind energy. Do not consider construction and maintenance costs.