Static Electricity (Edexcel GCSE Physics): Exam Questions

This question is about static electricity.

A student has a rubber balloon tied to a long piece of cotton thread.

The student gives the balloon an overall electrostatic charge.

i) Describe one way that the student could give the balloon an overall electrostatic charge.

[2]

ii) The student gives the balloon an overall negative charge.

Which of these sentences explains why the overall charge on the balloon is negative?

[1]

iii) The student charges another balloon on a long thread.

Explain how the student can show that the two balloons have the same type of charge.

[3]

Figure 9 shows a plastic block and a metal disc with an insulating handle.

The top surface of the plastic block has a negative charge.

The metal disc has no overall electric charge.

Figure 9

A student uses the insulating handle to hold the metal disc above the plastic block.

i) Which of these diagrams shows how the charge is distributed on the metal disc?

[1]

ii) The student keeps holding the metal disc above the charged plastic block and taps the metal disc with a finger.

This earths the metal disc for a short time.

Explain why the disc now has an overall positive charge.

[2]

iii) Figure 10 shows the charges on part of the metal disc and the plastic block.

Figure 10

On Figure 10, draw lines to show the shape and direction of the electric field between the metal disc and the plastic block.

[2]

A student gives a plastic strip an overall electric charge.

i) Describe one way that the student can give the plastic strip an overall electric charge.

[1]

ii) Figure 1 shows a gold leaf electroscope that can be used to investigate static electricity.

Figure 1

The electroscope has no overall charge.

The gold leaf has a very small mass and can bend very easily.

The student brings a negatively charged plastic strip near to the cap of the electroscope.

The gold leaf bends away from the metal rod. Which diagram shows the way that electric charge is now distributed?

[1]

Figure 2a shows another gold leaf electroscope that has been given an overall negative charge.

A student connects the metal cap of the charged electroscope to earth with a piece of wire as shown in Figure 2b.

Explain why the gold leaf has moved.

Two small objects, P and Q, are each given an electric charge.

Figure 3 represents the electric fields around the objects, P and Q.

Figure 3

i) Use information from Figure 3 to give two differences between the charge on P and the charge on Q.

[2]

ii) Object P and object Q are held near to each other so that their electric fields interact with each other.

State the effect that the electric field of object Q has on object P.

[1]

Figure 13 shows a negatively charged metal sphere, M.

Figure 13

i) Sphere M is negatively charged because it has

[1]

ii) A metal sphere, N, is connected to earth by a wire. N is moved near to M as shown in Figure 14.

Figure 14

A spark jumps between the spheres, discharging sphere M.

Describe what happens in the wire connecting sphere N to earth when the spark jumps between M and N.

[2]

iii) Describe a use of earthing in everyday life.

Your answer should state the use and describe why earthing is needed.

[2]

Figure 15 shows two parallel metal plates.

The plates are charged using a very high voltage.

Figure 15

Draw on Figure 15 the shape and direction of the electric field between the plates.

This question is about electrostatic charges and the forces between them.

Figure 16 shows some apparatus that can be used to show that like charges repel and unlike charges attract.

Figure 16

An acetate strip can be charged positively.

A polythene strip can be charged negatively.

A coulombmeter can be used to measure charge and whether the charge is positive or negative.

Explain how you would use the apparatus in Figure 16 to show that like charges repel and unlike charges attract.

Figure 1 shows a paint sprayer.

Figure 1

Some paint sprayers give the paint drops a positive charge as they leave the sprayer.

i) The paint drops have a positive charge because the sprayer

[1]

ii) Figure 2 shows the spray pattern from two different paint sprayers.

Figure 2

Sprayer X does not charge the paint drops. Sprayer Y gives the paint drops a positive charge.

Explain how charging the paint drops changes the shape of the spray pattern.

[2]

iii) Sprayer Y is used in a factory to paint a metal object.

The object hangs by a metal wire that is connected to earth.

Explain why a metal wire is used to connect the object to earth.

[2]

Figure 3 shows two charged metal plates.

Figure 3

The top plate has a negative electric charge.

The bottom plate has a positive electric charge.

On Figure 3, draw the electric field lines between the two plates and show the direction of this electric field.

A student uses a cloth to give a plastic rod a positive charge.

i) Explain how the rod becomes positively charged.

[3]

ii) Figure 12 shows four light balls, Q, R, S and T.

Each ball is suspended on a nylon string.

Balls Q, R and T are coated with a conducting material.

Ball S is an insulator.

Q and S have no charge, R is positively charged and T is negatively charged.

Figure 12

The student brings the positively charged rod near to each ball in turn.

Which ball is repelled by the positively charged rod?

Figure 13 shows part of a cloud, above the ground.

The base of the cloud is negatively charged.

Figure 13

Explain how lightning is produced between the cloud and the Earth.

Your answer should refer to induced charges.

You may add to the diagram in Figure 13 to help your answer.

Figure 14 shows fuel being transferred to an aeroplane.

Figure 14

Explain why transferring fuel can be dangerous and how the use of metal wires makes the process much safer.

A student rubs a plastic comb with a dry cloth to give the comb a positive electric charge.

Figure 6 shows the charged plastic comb picking up small pieces of paper.

Figure 6

i) Explain how rubbing the comb with a dry cloth gives the comb a positive electric charge.

[3]

ii) Explain how the positively-charged plastic comb picks up the small pieces of paper.

[3]

Which of these diagrams shows the shape and direction of the electric field around a positive point charge?

Figure 7 shows two metal spheres.

Metal sphere A is fixed to a table.

Metal sphere B can be moved.

Metal sphere B is placed at a short distance from metal sphere A.

Figure 7

Both spheres are insulated from the table and given a negative charge.

The force between the charged spheres is measured.

i) Explain, in terms of electric fields, why a force is exerted on sphere B.

[2]

ii) Sphere B is moved and the force between the spheres is measured at several different distances.

Figure 8 is a graph of force on sphere B against distance between the centres of the spheres.

Figure 8

Describe how the force on sphere B varies with the distance between the centres of the spheres.

[2]

Figure 1 shows a van der Graaff generator, a device that can reach extremely high voltages.

Figure 1

When the handle is turned, the dome becomes positively charged.

In terms of electron movement, give a reason why the metal dome becomes positively charged.

Calculate the energy transferred to an electron when it passes through a voltage of 180 kV.

Charge of an electron = 1.6 × 10^–19 C

When the van der Graaff generator is fully charged, it stores 3.5 × 10^–8 C of charge.

i) Calculate the number of electrons stored on a fully charged van der Graaff generator.

[2]

ii) The charge on the generator discharges through the air as a spark. 

The charge takes a time of 0.56 ms to leave the generator.

Calculate the mean (average) current in the air. Give the unit.

[3]

The metal dome is discharged. A thin metal case is then placed on top of the metal dome, as shown in Figure 2.

Figure 2 

i) When the handle is turned, the thin metal case moves upwards away from the dome.

Explain why the thin metal case starts to move upwards.

[3] 

ii) Explain why the metal case reaches a maximum height above the metal dome.

[4]

A student investigating static electricity charges two balloons and hangs them side by side. They observe the balloons do not hang vertically, as shown in Figure 1.

Figure 1

Explain why the cotton threads are not vertical.

The student charges the balloon by rubbing it with a cloth. The balloon becomes negatively charged.

i) Explain how the balloon becomes negatively charged.

[3]

ii) Compare the charge on the cloth compared to the balloon before and after rubbing the balloon.

[3]

The student investigates the effect of putting charged balloons on different surfaces. They put one charged balloon against a metal cabinet and one charged balloon against a wall.

i) Describe what happens to the charge on the balloon when it touches the metal cabinet.

[2]

ii) The student charges another balloon and holds it against a wall. The charged balloon sticks to the wall when he lets go.

Suggest why the balloon sticks to the wall.

[2]