Fig. 10.1 shows a motor lifting a mass. Fig. 10.2 shows part of the circuit diagram of the connections to the motor. [Figure 10.1 (motor lifting a mass)] [Figure 10.2 (partial circuit diagram with motor M and switch)]

1. (a)(i)The current in the motor is 1.5 A and the voltage supplied by the battery is 8.0 V. Complete the circuit diagram in Fig. 10.2 to show an ammeter and a voltmeter in the correct positions to take these measurements while the motor is working. [2][2]
2. (a)(ii)The motor takes 4.0 s to lift the mass. Calculate the electrical energy transferred to the motor in this time. energy = ..................................................... [2][2]
3. (a)(iii)The motor lifts the 150 g mass through a height of 80 cm in the 4.0 s. Calculate the gravitational potential energy gained by the mass. The gravitational field strength g = 10 N/kg. gravitational potential energy = ..................................................... [3][3]
4. (a)(iv)State two reasons why the gravitational potential energy gained by the mass is less than the electrical energy supplied to the motor. 1. ............................................................................................................................................................................ 2. ............................................................................................................................................................................ [2][2]
5. (b)(i)Fig. 10.3 shows the structure of the motor. When the mass reaches the top of its motion, the switch is opened. This disconnects the battery and causes the mass to fall. The coil turns as the mass falls. As the coil turns, a small voltage is produced. Explain why a voltage is produced as the coil turns. ............................................................................................................................................................................. ............................................................................................................................................................................. ............................................................................................................................................................................. [3][3]
6. (b)(ii)As the mass falls, a student connects a wire between the points A and B shown in Fig. 10.3. He notices that the mass takes a longer time to fall when the wire is connected. The student suggests that this is an example of Lenz's law. State Lenz's law and suggest why the mass takes longer to fall. ............................................................................................................................................................................. ............................................................................................................................................................................. ............................................................................................................................................................................. [3][3]

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