Permanent and induced magnetism, magnetic fields

This question is about magnetic fields.

Diagram 1 shows the poles of two strong bar magnets being held close together.

There is a uniform magnetic field between the poles of the bar magnets.

Complete diagram 1 by drawing magnetic field lines to show the uniform magnetic field.

You should label the poles of the bar magnets.

Diagram 2 shows a strong magnet attracting an iron block.

The iron block becomes magnetised when it is in the magnetic field of the strong magnet.

Label the magnetic poles on the magnetised iron block in diagram 2.

A student takes the strong magnet away from the iron block.

The student suggests they can permanently use the iron block to attract small pieces of iron.

Explain whether the student’s suggestion is correct.

Diagram 1 shows two magnetic poles.

Draw three field lines on Diagram 1 to show the uniform magnetic field in the shaded region between the two poles.

Diagram 2 shows a current‑carrying wire in the uniform magnetic field between the poles of a magnet.

The arrow on the wire shows the direction of current.

Draw another arrow on Diagram 2 to show the direction of the force on the wire.

Diagram 3 shows a rectangular loop of wire carrying a current in a uniform magnetic field.

Explain why the loop starts to turn but stops when the loop is vertical.

Diagram 1 shows the magnetic field lines near the south pole of a bar magnet.

Draw two arrows on the field lines in diagram 1 to show the direction of the magnetic field lines.

Which of these is attracted to the bar magnet if placed in the magnetic field?

The strength of the magnetic field changes as the distance from the south pole increases.

Explain how the magnetic field lines show this.

Diagram 2 shows a small piece of iron that has been placed in the magnetic field.

The piece of iron becomes magnetised when placed in the magnetic field.

Explain why the piece of iron experiences a force towards the south pole of the bar magnet.

You may add to diagram 2 to help your answer.

A student suggests that the piece of iron is now a permanent magnet.

Explain why the student is incorrect.

This question is about magnets.

Which of these substances is not attracted to a bar magnet?

Diagram 1 shows a bar magnet.

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Diagram 1

Draw magnetic field lines on diagram 1 to show the shape and direction of the magnetic field around the bar magnet.

Some bar magnets are made of steel.

Explain why steel is a good material for making bar magnets.

Draw an arrow on diagram 2 to show the direction of the force on the wire due to the magnetic field.

Assume that the magnetic field is uniform.

State two changes that could be made that would decrease the magnitude of the force on the wire in diagram 2.

Diagram 1 shows the magnetic field between the poles of two strong bar magnets.

Add labels to diagram 1 to show the poles of the bar magnets.

The bar magnets are made from steel.

Give one reason why steel is a good material for making bar magnets.

Explain how diagram 1 shows a uniform magnetic field.

Diagram 2 shows a metal wire being moved downwards through the uniform field between the poles of the same bar magnets. The orientation of the magnets has not been changed.

Give a reason why a voltage is induced between the ends of the metal wire as it moves between the poles of the bar magnets.

State two changes that could be made to this arrangement that would increase the magnitude of the induced voltage.

The diagrams show some equipment that the physicist Ørsted used in an investigation in 1820.

Diagram 1 shows the position of eight compass needles around a wire with no current in the wire.

The compass needles line up with and show the direction of the Earth’s magnetic field lines.

Diagram 2 shows the position of the same compass needles when a current is in the wire.

Diagram 2

Explain why the compass needles turn when the current is switched on.

Using evidence from the compass needles in diagram 2, draw on diagram 2 the shape and direction of a magnetic field line produced by the current in the wire.

Suggest what happens to the magnetic field when the current in the wire is reversed.

The current in the wire is turned off.

Diagram 3 shows the wire placed in a uniform magnetic field.

Diagram 3

The current is now switched on.

Draw an arrow to show the direction of the force on the wire.

The power supply in diagram 3 is replaced by an ammeter.

When the wire is moved, a current is detected.

Explain which direction the wire is moved in the magnetic field to produce a current in the wire.

Explain why a current is produced in the wire when the wire is moved in the magnetic field.

This question is about magnetic fields.

A student positions a thick wire vertically through the centre of a horizontal card.

The student then passes a constant current through the wire in the downward direction, as shown in diagram 1.

On diagram 1, draw the shape and direction of the magnetic field produced by the current in the wire.

Describe a method the student could use to show the shape of the magnetic field produced by the current in the wire.

The student then removes the card and sets up a second wire next to the first wire, as shown in diagram 2.

The current in both wires is in the downward direction.

The student observes that the wires move towards each other.

Explain why the wires move towards each other.

The region of space around a magnet is known as a magnetic field.

Which of these diagrams correctly represents the magnetic field around a bar magnet?

The diagram shows two bar magnets placed close together.

Which of these describes what happens to the two magnets?

Which of these magnet arrangements gives a uniform field between the poles?

State the name of a material that would be suitable for use as a permanent magnet.

Describe an investigation that could be used to determine the shape of the magnetic field around a bar magnet.

A student uses this apparatus to measure the force of repulsion between magnet A and magnet B.

Magnet A is clamped in a fixed position.

Magnet B is resting on a balance.

Give a reason why the two magnets shown in the diagram will repel each other.

Give a reason why the top plate of the balance is not affected by the magnetic fields of the magnets.

Complete the diagram by drawing the shape and direction of the magnetic field pattern between the magnets.

In the position shown, the balance reading is 1.6 N.

Explain how the balance reading will change if magnet A is brought closer to magnet B.

Explain how the balance reading will change if the poles of magnet A are reversed but the distance between the magnets remains constant.

Very strong magnets can be made using the element neodymium.

Diagram 1 shows parts of two neodymium magnets, X and Y, when they are held close together.

Diagram 1

A uniform magnetic field is produced in the space between the magnets.

Diagram 1 shows the south pole of magnet X.

Complete diagram 1 by drawing the uniform magnetic field and labelling the pole on magnet Y.

Diagram 2 shows another neodymium magnet being used to lift an iron ball from a table.

The iron ball is shown at the instant it leaves the surface of the table.

Diagram 2

Explain why the iron ball experiences an upward magnetic force.

The iron ball experiences an upward resultant force at the instant shown in diagram 2.

Draw a labelled arrow on diagram 2 to show the weight of the iron ball.

State the formula linking weight, mass and gravitational field strength.

At the instant shown in diagram 2, the resultant force acting on the iron ball is 124 mN and the magnetic force is 165 mN.

Calculate the mass of the iron ball.

Explain why the resultant force acting on the iron ball increases as the iron ball moves towards the magnet.

The diagram shows a bar magnet.

Draw four magnetic field lines around the bar magnet.

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The diagram shows a loop of wire connected to the terminals of a voltmeter.

Explain why the voltmeter reading changes from zero when the magnet is moved near the loop of wire.

The diagram shows an air track that can be used to investigate motion without friction.

Air comes out through a series of small holes in the air track, which lifts the gliders slightly above the track.

There are two gliders on the track.

Each glider has a magnet.

The poles of the magnets nearest each other are alike.

Explain the direction of the force acting on magnet A from magnet B.

The gliders collide and the magnets cause them to rebound.

Before the collision, the momentum of glider A is 0.045 kg m/s to the right and glider B is at rest.

State the total momentum of glider A and glider B after the collision.

After the collision, the momentum of glider A is 0.021 kg m/s to the left.

Calculate the momentum of glider B after the collision.

momentum of glider B =_........ kg m/s

The time taken for glider B to change its momentum is 0.19 seconds.

Calculate the average force on glider B that causes this change in momentum.

Give the direction of the force on glider B from glider A.

Transformers are useful in the transmission of electricity.

The diagram shows a step‑down transformer.

Give the name of a suitable metal that could be used in the core of the transformer.

State the formula linking input power and output power for a transformer.

The step‑down transformer has an input voltage of 275 kV and an output voltage of 230 V.

The transformer has an output current of 95 A.

Calculate the input current to the transformer.

Assume the transformer is 100% efficient.

Explain how transformers are useful in the large‑scale transmission of electricity.

You may draw a diagram to support your answer.

This question is about bar magnets.

Describe an investigation to show the shape and direction of the magnetic field for a bar magnet.

You may draw a diagram to help your answer.

A bar magnet is used in a bicycle dynamo.

The diagram shows a cross-section of a bicycle dynamo.

The dynamo has a rotating wheel that presses against the tyre of the bicycle.

The rotating wheel is connected to a bar magnet by a spindle.

When the rotating wheel spins, the bar magnet spins.

The dynamo is connected to the lights on the bicycle.

Explain how the dynamo causes the lights to turn on when the bicycle is moving.

Suggest a disadvantage of using the dynamo to power the bicycle lights.

The passage describes some of the properties of magnets and magnetic fields.

Use words from the box to complete the passage.

Each word may be used once, more than once or not at all.

The north pole of one magnet will repel the_........ pole of another magnet.

There is attraction between_........ and magnets.

Materials that are difficult to magnetise are called_........ magnetic materials.

The direction of the magnetic field lines for a magnet is from_........ to south.

Iron is a_........ magnetic material.

This question is about a proton moving in a uniform magnetic field.

Describe how to use two permanent magnets to produce a uniform magnetic field.

You may draw a diagram to support your answer.

The diagram shows a proton moving in a circular path at constant speed in a uniform magnetic field.

This motion is similar to the movement of a planet in the Solar System.

Draw an arrow to show the direction of the force on the proton.

Accurately measure the diameter of the proton’s path.

The proton completes one orbit of its circular path in a time period of 8.7 × 10^–6 seconds.

Calculate the orbital speed of the proton.

A student investigates the magnetic fields produced by magnets.

Describe a method he could use to determine the shape and direction of the magnetic field produced by a bar magnet.

You may use a diagram to help your answer.

The diagram shows the shape of the magnetic field around the bar magnet.

Add two arrows to the diagram to show the direction of the magnetic field.

Explain how the diagram shows that the strength of the magnetic field changes.

Magnetic field strength can be measured in units of milli-tesla (mT).

A student uses a different magnet.

The student measures the magnetic field strength at different distances from the north pole of this magnet.

The graph shows his results.

The student concludes that his results obey this relationship.

magnetic field strength × distance² = constant

Use data from the graph to deduce whether the student’s results support this conclusion.