A fixed resistor in the speed controller of a model railway carries a current of 0.40 A and dissipates energy at a rate of 1.6 W. On a slower setting, the current in the resistor is reduced to 0.20 A. The resistance of the resistor does not change.
Predict the power dissipated in the resistor on the slower setting.
105 exam-style questions on Edexcel GCSE Physics 10.3 Electrical energy and power, covering 10.3.1 The heating effect of an electric current, 10.3.2 Reducing energy transfer in wires, 10.3.3 Advantages and disadvantages of the heating effect, 10.3.4 Energy transferred by an electrical circuit, 10.3.5 Electrical power, and 10.3.6 Energy transfers in domestic devices. Each one has a worked solution and a mark scheme showing where the marks go.