P2, Chapter 5 Name …………………………………………………….………… Class ………………………….. Mains electricity 1 The pictures show situations in which electricity is not being used safely. For each picture a, b and c, explain how electricity is not being used safely. ...................................................................... ...................................................................(2) ...................................................................... ...................................................................(2) ...................................................................... ......................................................................... (2) d The colour of the earth wire in a plug is ………………………………… e The pins of the plug are made of brass because it is a good f (1) …………………………… (1) The voltage on the neutral wire is about …………………… V. (1) New AQA GCSE Science © Nelson Thornes Ltd 2011 1 P2, Chapter 5 Name …………………………………………………….………… g 2 Class ………………………….. RCCB stands for ……………………………………………………….. (1) Most domestic appliances are connected to the 230 V mains supply with a 3-pin plug containing a fuse. 3 A, 5 A and 13 A fuses are available. a A bulb for a desk lamp has a normal current of 0.26 A. i Which of the three fuses should be used? ................................................................................................................................... ................................................................................................................................... ii (1) Calculate the power of the lamp. ................................................................................................................................... ................................................................................................................................... iii (2) Calculate how many coulombs of charge pass through the lamp if it is left on for 1 hour? ................................................................................................................................... ................................................................................................................................... b i Calculate the current passing through a 1.15 kW electric fan heater. ................................................................................................................................... ii [H] (6) (2) Which fuse should be used in the plug for this heater? ................................................................................................................................... ................................................................................................................................... New AQA GCSE Science © Nelson Thornes Ltd 2011 (1) 2 P2, Chapter 5 Name …………………………………………………….………… c Class ………………………….. Calculate how much electrical energy is transferred when the fan heater is left on for 30 minutes. Write down the equation you use. Show clearly how you work out your answer and give the unit. ................................................................................................................................... ................................................................................................................................... d (3) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. The heater is made of metal and has an earth wire connected to it. Explain how the fuse and earth wire together protect the wiring of the circuit. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... New AQA GCSE Science © Nelson Thornes Ltd 2011 (6) 3 P2, Chapter 5 Name …………………………………………………….………… 3 Class ………………………….. A kettle is connected to the UK mains supply and boiled. An energy monitoring device measures that 420 000 J has been transferred to the kettle in the time it takes to boil. a Calculate how much charge has flowed through the kettle. Write down the equation you use. Show clearly how you work out your answer and give the unit. ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... b [H] (3) The power of the kettle is 2.2 kW. How long did the kettle take to boil? ................................................................................................................................... ................................................................................................................................... ................................................................................................................................... 4 (3) An oscilloscope is connected to a power supply. The trace is shown on a centimetre grid. a Explain How do you know that it is an ac supply being measured? ................................................................................................................................... New AQA GCSE Science © Nelson Thornes Ltd 2011 (1) 4 P2, Chapter 5 Name …………………………………………………….………… b Class ………………………….. Give the peak voltage if each division on the y-axis is 2 V/cm. ................................................................................................................................... c (1) Each x-axis division is 0.01 s/cm. i Calculate the time period of the supply. ................................................................................................................................... ii (1) Calculate the frequency of the supply. ................................................................................................................................... ................................................................................................................................... d [H] (2) Describe the position and appearance of the trace on the screen if the supply was switched to 6 V dc. ................................................................................................................................... ................................................................................................................................... New AQA GCSE Science © Nelson Thornes Ltd 2011 (2) 5
