Energy resourcesIB MYP Physics: Mind map

Exam questions on Energy resources

1. A country that gets most of its electricity from one old coal-fired power station is planning to add wind turbines and solar panels to its energy mix.
   Explain why wind turbines are less reliable than a coal-fired power station.2 marks
2. A mountain region in Switzerland has a pumped-storage hydroelectric station. Two reservoirs, one high up the mountain and one in the valley below, are joined by pipes containing a pump and a turbine. At night, when demand for electricity is low, surplus electricity from the grid is used to pump water up to the upper reservoir. During the evening peak in demand, the water is released back down.
   Explain how electricity is generated when the water is released.2 marks
3. Students investigate whether the number of blades on a model wind turbine affects the voltage it generates. They place the turbine 50 cm from a fan on the same speed setting and measure the voltage with a voltmeter. The voltage was 0.8 V with 2 blades, 1.1 V with 3 blades, 1.4 V with 4 blades, 1.5 V with 6 blades and 1.4 V with 8 blades.
   State a testable hypothesis for this investigation, giving a scientific reason, and name one variable that must be controlled.3 marks