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H.W.Q &A
Electrical circuits
Current electricity
Circuits
(PB pages 38 and 39)

1- Describe the path of an electron round the circuit in figure 4.1 when the switch is pressed down.
Answer:-1) An electron moves from the negative terminal of the battery along the wire, through the switch contacts and the lamp filament to the positive terminal.


2- a) How does the wire in the filament behave differently to other wires in the circuit when the current flows?
Answer: - 2-a)
it releases light and heat.


2-b) what property of the wire accounts for this difference?
Answer:-2-b)
It is more resistant to the flow of electrons than the other wires in the circuit.


3-In figure 4.1 ( page 38), the base of the cell( on the right) is the negative terminal and the cap ( on the (on the left) is the positive terminal, How can you distinguish between the positive and negative terminals in a cell in a circuit diagram?
Answer-3) the positive terminal is represented by a long vertical line and the negative terminal is a shorter line.


Other circuit components
(PB pages 40, 41 and 42)
4) How does the length of a high resistance wire affect the flow of current through the circuit?
Answer 4) the longer the length of wire the greater the resistance it offers.


5) In figure 4.6 which way should the contact be moved to?
a) Increase.
b) Decrease.
Answer 5-a) To the right .
5-b) To the left.


6) Figure 4.7 shows a variable resistor in a dimmer switch to make the lights
a) Brighter
b) Dimmer?
Explain your answer.
Answer 6-a) Clockwise.
6-b) Anticlockwise.
Less resistance is included in the circuit when the switch is turned clockwise so the lights become brighter.
More resistance is included in the circuit when the switch is turned anticlockwise so the lights become dimmer

Fuses and circuit breakers
How could you prevent a fire in the home being caused by an electrical fault?
Answer 1) By checking all cables to make sure that none of the insulation is worn and by not plugging too many appliances into one socket.


2- why should you always switch off a circuit before replacing a fuse ?
Answer 2) There is a danger that you may complete the circuit and receive a harmful shock.