Permanent & induced magnetism, magnetic fields

A student uses a special pen to write notes on an electronic tablet.

There is a bar magnet inside the pen and a bar magnet inside the tablet.

Figure 9 shows the pen and tablet being held together by the magnets.

The bar magnets in the tablet and pen attract each other.

What name is given to pole X and to pole Y in Figure 9 ?

Give the reason for your answer.

A student investigated the maximum distance from where the pen moves back to

the tablet.

This is the method used.

1. Place the edge of the tablet at 0 cm on a ruler.

2. Place the pen 0.5 cm away from the tablet.

3. Release the pen.

4. If the pen moves to the tablet, repeat steps 2, 3 and 4 using a greater distance.

5. Record the greatest distance from where the pen moves back to the tablet.

Figure 10 shows the apparatus.

The student repeated the investigation.

The distances recorded by the student were:

4.0 cm 3.5 cm 4.0 cm 3.5 cm 4.5 cm

What was the range of distances recorded by the student?

Calculate the mean of the distances recorded by the student.

Complete the sentence.

Choose the answer from the box.

Repeating and calculating a mean reduces the effect

Describe how the size of the magnetic force on the pen changed as the pen was moved away from the tablet.

What material could the magnet in the pen be made of?

Tick () one box.

The student used four plotting compasses to show the magnetic field pattern around the pen.

Figure 11 shows the pen and the outline of the plotting compasses.

Draw one arrow inside each compass on Figure 11 to show which direction the compass needle points.

One arrow has been drawn for you.

Figure 8 shows a permanent magnet and two magnetic compasses.

The poles of the magnet are labelled X and Y.

The direction of the compass needle in compass A is shown.

Give the names of the poles labelled X and Y in Figure 8.

Draw an arrow on compass B in Figure 8 to show the direction of the magnetic field at that position.

Figure 9 shows security tags on some clothes in a shop.

Security tags can be detected if clothes are taken out of the shop with tags still attached.

The tags are attached to the clothes by pins made from a magnetic material.

A shop assistant can use a magnet to remove the pins.

Which of the following are magnetic materials?

Tick () two boxes.

Which of the following describes the force between a magnetic material and a magnet?

Tick () one box.

The shop assistant removes a security tag and drops the tag into a collecting bin.

As it falls, the tag accelerates at 9.8 m/s².

The mass of the tag is 0.030 kg.

Calculate the resultant force acting on the tag.

Use the equation:

resultant force = mass × acceleration

Figure 4 shows iron filings sprinkled around a bar magnet.

Why are the iron filings attracted to the bar magnet? Tick (✓) one box.

Figure 5 shows a bar magnet. Draw magnetic field lines to show the magnetic field pattern around the bar magnet. You should add arrows to the field lines to show the direction of the magnetic field.

Figure 5

Figure 6 shows two bar magnets.

Figure 6

The magnets attract each other. What conclusion can be made about the two poles marked X and Y ? Tick (✓) one box.

Figure 7 shows some plotting compasses around a wire. There is no current in

the wire.

Why do the plotting compasses all point in the same direction?

When the switch is closed there is a current in the wire. The current creates a magnetic field. What shape are the magnetic field lines around the wire? Tick (✓) one box.

A student investigated the force exerted by an electromagnet on a paper clip.

The student varied the distance between the paper clip and the electromagnet. Figure 8 shows the equipment used.

The student recorded the reading on the newtonmeter for several different distances.

The current in the electromagnet was the same for each distance. Complete the sentence. Choose the answer from the box.

In the investigation, the current was variable.

What is the size of the downward force on the paper clip in Figure 8 ?

The distance between the paper clip and the electromagnet is increased. What happens to the size of the downward force?

A teacher demonstrated the motor effect. Figure 5 shows the equipment used. The equipment includes a permanent magnet.

The copper rod remains stationary while the switch is open. Complete the sentence. The tendency for an object to remain stationary is

When the switch is closed the copper rod accelerates.

In which direction will the copper rod accelerate? Tick (✓) one box.

Explain one way the teacher could increase the acceleration of the copper rod.

The magnet used in the demonstration was a permanent magnet. Figure 6 shows an iron bar and a permanent magnet.

Describe how the permanent magnet could be used to test if the iron bar is also a permanent magnet.

Figure 7 shows a magnetic compass used by walkers.

Explain how a magnetic compass provides evidence that the Earth has a magnetic field.

Figure 5 shows a compass.

Why does the compass always point in the same direction when it is not near a magnet? Tick (✓) one box.

What material could the needle of the compass be made from? Tick (✓) one box.

Figure 6 shows a coil of wire.

There is a current in the coil. The circles show the position of four compasses.

Which statement describes the magnetic field around the coil? Tick (✓) one box.

Draw one arrow in each circle on Figure 6 to show the direction of the magnetic field at that point.

Give two ways the magnetic field around the coil could be made stronger.

Magnets attract some metals.

Which diagram shows the correct magnetic field pattern for a bar magnet?

Tick (✓) one box.

Figure 3 shows an iron bar near a permanent magnet.

The iron bar becomes an induced magnet.

Label the poles on the iron bar.

The magnet is turned around so that the north pole is closest to the iron bar.

Which statement about the iron bar is true?

Tick (✓) one box.

Figure 4 shows an electromagnet being used to separate pieces of different types of

metal on a conveyor belt.

Which two of the following types of metal would be attracted to the electromagnet?

Tick (✓) two boxes.

What is an advantage of using an electromagnet instead of a permanent magnet to separate the types of metal?

Tick (✓) one box.

Figure 5 shows a simple electromagnet.

What is the purpose of the iron nail inside the coil of wire?

Tick (✓) one box.

Which of the following would increase the strength of the electromagnet?

Tick (✓) one box.

Figure 4 shows the magnetic field pattern around a permanent magnet.

Where is the magnetic field of the magnet the strongest?

How does Figure 4 show that the strength of the magnetic field is not the same at all places?

Figure 5 shows an electromagnet being used to separate iron and steel from

non-magnetic metals.

Explain one reason why an electromagnet is used instead of a permanent magnet.

Pieces of iron and steel are attracted to the electromagnet. Name two other metals that would be attracted to the electromagnet.

The design of the electromagnet cannot be changed. Give two ways the force exerted by the electromagnet on a piece of iron or steel could be increased.

The conveyor belt that moves the pieces of metal is driven by an electric motor.

Figure 6 shows a simple electric motor.

The length of the wire AB in the magnetic field is 120 mm. There is a current of 4.0 A in the wire. The length of wire AB experiences a force of 0.36 N. Calculate the magnetic flux density between the magnets. Give the unit.

Fleming’s left-hand rule can be used to determine the direction of the force on wire AB. Complete the labels on Figure 7 to show Fleming’s left-hand rule.

Figure 9 shows five different metal samples.

A student placed a magnet close to each metal sample. Describe what happened.

Figure 10 shows a paper clip being attracted to a permanent magnet.

The paper clip in Figure 10 is not a permanent magnet. Explain what would happen if the paper clip was removed and brought close to the south pole of the permanent magnet.

Write down the equation that links gravitational field strength (g), mass (m) and weight (W).

The student added more paperclips to one end of the magnet. The maximum number of paperclips the magnet could hold was 20 Each paper clip had a mass of 1.0 g gravitational field strength = 9.8 N/kg Calculate the maximum force the magnet can exert.

Figure 1 shows five different metal samples.

A student placed a magnet close to each metal sample. Describe what happened.

Figure 2 shows a paper clip being attracted to a permanent magnet.

The paper clip in Figure 2 is not a permanent magnet. Explain what would happen if the paper clip was removed and brought close to the south pole of the permanent magnet.

Write down the equation that links gravitational field strength (g), mass (m) and weight (W).

The student added more paperclips to one end of the magnet. The maximum number of paperclips the magnet could hold was 20 Each paper clip had a mass of 1.0 g gravitational field strength = 9.8 N/kg Calculate the maximum force the magnet can exert.

Magnetic force is a non-contact force.

Figure 1 shows a bar magnet.

Which letter shows the position where the magnetic field around the bar magnet is strongest?

Tick (✓) one box.

When two magnets are brought close to each other they exert a force on each other.

Describe how two bar magnets can be used to demonstrate a force of attraction and a force of repulsion.

Force of attraction

Force of repulsion

Figure 2 shows some paper clips that are attracted to a permanent magnet.

The paperclips become magnetised when they are close to the permanent magnet.

What is the name of this type of magnetism?

Tick (✓) one box.

Label the north and south poles of the two magnetised paper clips in Figure 2.

A magnet produces a magnetic field.

Which diagram shows the magnetic field pattern around a bar magnet?

Tick one box.

Figure 13 shows three metal blocks.

The blocks are not labelled.

One block is a permanent magnet, one is iron and one is aluminium.

Describe how another permanent magnet can be used to identify the blocks.

Figure 14 shows a toy crane.

The toy crane uses an electromagnet to pick up and move the blocks.

Explain how this electromagnet is able to pick up and move the blocks.

A magnet produces a magnetic field.

Which diagram shows the magnetic field pattern around a bar magnet? Tick one box.

Figure 3 shows three metal blocks. The blocks are not labelled. One block is a permanent magnet, one is iron and one is aluminium.

Describe how another permanent magnet can be used to identify the blocks.

Figure 4 shows a toy crane.

The toy crane uses an electromagnet to pick up and move the blocks. Explain how this electromagnet is able to pick up and move the blocks.