State two energy resources that do not have the Sun as their original source of energy.
An underwater tidal turbine is used to generate electricity. The useful electrical energy output from the turbine in 1.0 s1.0\text{ s}1.0 s is 15 000 J15\ 000\text{ J}15 000 J. The kinetic energy of the water hitting the turbine in 1.0 s1.0\text{ s}1.0 s is 25 000 J25\ 000\text{ J}25 000 J. The velocity of the water hitting the turbine is 2.2 m/s2.2\text{ m/s}2.2 m/s.
Show that the mass of water hitting the turbine each second is approximately 10 300 kg10\ 300\text{ kg}10 300 kg.
Calculate the efficiency of the turbine.
Solar energy and geothermal energy are both renewable energy resources. Suggest one reason why geothermal energy is a more reliable energy resource than solar energy.
142 exam-style questions on CIE IGCSE Physics 1.7.3 Energy resources. Each one has a worked solution and a mark scheme showing where the marks go.