1. A plastic rod is rubbed with a woollen cloth. It becomes positively charged.

a) Why does the plastic become positively charged?

b) If a glass cabinet is polished with a dry cloth, why does it quickly become dusty again?

c) Photocopiers use electrostatic charge in order to work. The following sentences describe how a photocopier works. Put them in the correct order.

A. A strong light copies the image on the page.

B. The areas on the roller which are charged attract the black toner powder particles.

C. The charge that’s left on the roller has an identical pattern to the dark regions of the page being copied.

D. The toner powder melts onto the page and is now a photocopy of the original.

E. A charge is given to a roller which is coated with photo-conducting material.

F. The charge leaks away from the roller where it’s hit with light.

G. A piece of blank paper is heated up and pressed up against the roller.

E ___ ___ ___ ___ ___ D

2. A man touches a live wire inside a mains electricity socket and receives an electric shock. The mains electricity socket has a potential difference of 230 volts and the total resistance to the current flow is 50 k?.

a) Calculate the current that will flow through the man.

b) The man calls in an electrician to fix the socket. The electrician wears rubber soled boots. Explain why this is a good idea while working.

3. A circuit is made up of two bulbs, a switch and battery.

a) Draw a series circuit with these components.

b) Draw a parallel circuit with there components.

c) Explain how the current flowing through the components in the series circuit and parallel circuit is different.

d) To measure the amps in the circuit you use an ammeter. How must you connect an ammeter in a circuit?

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ANSWERS

1. a) Electrons are transferred from the cloth to the plastic rod.

b) The glass panels of the cabinet become positively charged which attracts the negatively charged dust.

c) E A F C B G D

2. a) 230 / 50000 = 0.0046 mA

b) It increases their overall resistance and means that if they do get shocked the current will be smaller.

3. a) –

b) –

c) In a series circuit the current which flows through each component is the same and in a parallel circuit the current is shared between the components.

d)In series.

Section complete – Top effort!

Carry on with revising GCSE Physics – Next topic: Methods to Generate Electricity