Combined Science: Trilogy 8464: P2.Electricity Topical Past Paper Questions

A student investigated how the current in a red LED varies with the potential difference across the LED. Figure 3 shows an incomplete diagram of the circuit used. Figure 3 1 Complete Figure 3 to show how the student should have connected a voltmeter and an ammeter into the circui…

Figure 7 shows how the National Grid transfers energy from a power station to some street lamps. Figure 7 1 Explain how transformer X increases the efficiency of the National Grid. [3 marks] 2 The potential difference across the primary coil in transformer Y is 400 000 V. The pot…

The camera in a mobile phone uses an LED to provide light when taking a photograph. A student investigated how the potential difference across an LED varies with the current in it. Figure 9 shows the circuit used. Figure 9 1 The student closed the switch. The voltmeter gave a rea…