Energy from the Sun evaporates water from the sea. Some of this water eventually drives a hydroelectric power station. Give an account of the physical processes and energy changes involved.
In a hydroelectric power station, 2.5×105 kg2.5 \times 10^5\text{ kg}2.5×105 kg of water per second fall through a vertical distance of 150 m150\text{ m}150 m. The water passes through turbines to generate electricity, and leaves the turbines with a speed of 16 m/s16\text{ m/s}16 m/s.
Calculate the gravitational potential energy lost by the water in 1 second. Use g=10 m/s2g = 10\text{ m/s}^2g=10 m/s2.
Calculate the kinetic energy of the water leaving the turbines in 1 second.
533 exam-style questions on CIE IGCSE Physics 1.7 Energy, work and power, covering 1.7.1a Energy stores and energy transfers, 1.7.1b Conservation of energy, 1.7.1c Kinetic and gravitational potential energy, 1.7.2 Work done, 1.7.3 Energy resources, 1.7.3a Energy resources and electricity generation, 1.7.3b Nuclear fusion as an energy source, 1.7.3c Efficiency of energy transfer, and 1.7.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.