A filament lamp is connected to a 240V alternating current (a.c.) mains supply.

1. (a)Describe how the output of an a.c. supply differs from the output of a direct current (d.c.) supply. Sketch two voltage-time graphs in the blank space to help your explanation.[3]
2. (b)(i)The lamp is rated at 60W and is designed to be used with a 240V supply. Calculate the current in the lamp. current =[2]
3. (b)(ii)Calculate the resistance of the lamp. resistance =[2]
4. (b)(iii)A room is lit by five of these filament lamps connected in parallel. State two advantages of connecting the lamps in parallel rather than in series. 1. 2.[2]
5. (b)(iv)The five lamps in (b)(iii) are lit for an average time of 5.5 hours a day for a year. Electricity costs $0.15/kWh. Calculate the cost of using these lamps for a year. cost =[2]
6. (c)(i)A student takes the lamp in (b) to school and connects it in a circuit using a 1.5V cell, an ammeter and a voltmeter. The circuit is used to determine the resistance of the lamp. In the blank space, draw the circuit diagram of the circuit used to determine the resistance of the lamp.[2]
7. (c)(ii)The value of the resistance of the filament lamp in this circuit differs greatly from the value calculated in (b)(ii). State how the resistance value in this circuit differs and explain why it differs.[2]