Paper 1 H - SAMPLE SET 1 Q13
13) An electrician is replacing an old electric shower with a new one.
The inside of the old shower is shown in Figure 19.
The inside of the old shower is shown in Figure 19.
13.1) If the electrician touches the live wire he will receive an electric shock.
Explain why. [4 marks]
Different electrical wires need to have a cross-sectional area that is suitable for the power output.
Figure 20 shows the recommended maximum power input to wires of different cross-sectional areas.
Explain why. [4 marks]
Different electrical wires need to have a cross-sectional area that is suitable for the power output.
Figure 20 shows the recommended maximum power input to wires of different cross-sectional areas.
13.2) The new electric shower has a power input of 13.8 kW.
Determine the minimum diameter of wire that should be used for the new shower.
The diameter, d, can be calculated using the equation:
Determine the minimum diameter of wire that should be used for the new shower.
The diameter, d, can be calculated using the equation:
A is the cross-sectional area of the wire. [2 marks]
Minimum diameter = _________ mm
13.3) The charge that flows through the new shower in 300 seconds is 18 000 C. The new electric shower has a power of 13.8 kW.
Calculate the resistance of the heating element in the new shower.
Write down any equations you use. [5 marks]
Calculate the resistance of the heating element in the new shower.
Write down any equations you use. [5 marks]
Resistance = __________ Ω
(Total for Question 13 = 11 marks)
(Total for Question 13 = 11 marks)