Static Electricity

Describe, in terms of particles, what happens as the rod becomes negatively charged.

Explain, in terms of particles, how an electrical conductor differs from an electrical insulator.

The conducting surface of the ball contains both negatively charged particles and positively charged particles.

Explain what happens to the negatively charged particles and to the positively charged particles as the rod is brought close to the ball.

Explain why the resultant force on the ball is towards the rod.

Explain, in terms of particles, how the rod becomes charged and state what happens to the cloth.

Fig. 8.1 shows a metal sphere X on a plastic stand.

Explain why metals are electrical conductors and why plastics are electrical insulators.

By drawing on Fig. 8.2, show the distribution of charge on X.

An earth wire is now connected to the metal sphere as shown in Fig. 8.3.

State what happens to the charges on the sphere as the earth wire is connected.

______

The earth wire in (ii) stays connected to the metal sphere.

Describe the distribution of charge on the sphere.

The earth wire is disconnected from the sphere and then the negatively charged rod is moved away from the sphere.

Explain what happens to the charges on the sphere as the charged rod is moved away.

State what is meant by 'electric field'.

Fig. 8.4 shows the negatively charged sphere Y. The negative charges are not shown.

On Fig. 8.4, draw the pattern and mark the direction of the electric field lines surrounding sphere Y.

Explain, in terms of particles, why the rod is now positively charged.

State what happens to the woollen cloth.

On Fig. 5.1, draw the distribution of charge on the sphere.

Explain why the sphere is pulled towards the rod.

Fig. 5.1 shows part of a machine used to investigate electrostatic charging.

Before the machine is switched on the metal dome and the ball are uncharged.

When the machine is switched on, the metal dome becomes negatively charged.

Explain how charging the dome causes the metal ball P to become positively charged.

A photocopier works using electrostatic charging. It contains a drum whose surface conducts charge where it is exposed to light.

Fig. 5.2 shows a piece of paper, the drum and the heater of a photocopier.

The photocopier produces a copy of an original page on a piece of paper.

The sentences below describe the process of making the copy but the sentences are in the wrong order.

A The drum is given a positive charge.

B The positively charged parts of the drum attract a black powder.

C Where light hits the drum, the positive charge leaks away.

D An image of the original page is projected onto the drum.

E The drum rolls against a piece of paper, transferring powder to the paper.

F The paper is heated which makes the black powder stick to it.

Arrange the sentences in the correct order. The first and last sentences are already in the correct boxes.

A person walks across a carpet. As he touches a door handle he receives an electric shock.

Suggest why this happens.

The drops in Fig. 7.1 spread out more as they leave the nozzle than those in Fig. 7.2.

Explain why.

Explain why the paint reaches the back of the leg in Fig. 7.1.

State how the structure of an insulator differs from that of a conductor and give one example of an insulator.

On Fig. 5.1, draw the charges on K and on L.

The positively charged rod is moved away.

State what happens to the charge on K.

______

An earthing wire is connected to sphere L.

State what happens to the charge on L.

______

State how Fig. 8.1 shows that the rod and the cloth are uncharged.

Describe what happens to the charges on the rod and on the cloth during the charging process.

Describe a simple experiment to show that the plastic rod is charged.

You may draw a diagram if you wish.

State a material that is an electrical insulator.

On Fig. 7.1, draw the distribution of charges on P.

On Fig. 7.2, show the distribution of charges on P with the earth wire connected.

with the earth wire still connected to P,

after the earth wire is disconnected from P.

Explain how rubbing causes the balloon to become negatively charged.

Explain why the hair is pulled towards the balloon.

Explain why it is important that the balloon is made from an electrical insulator.

State one example where static electricity is useful.

On Fig. 5.1, draw the induced charges on sphere U.

State and explain what happens to the charge on the two spheres as they touch.

charge on C: ______
charge on U: ______

Explain why U is repelled by C.