An insulated wire wound into the shape of a spring.

Very pure iron that cannot be made into a permanent magnet.

Describes the relationship between two variables, in which doubling the value of one variable doubles the value of the other.

These show the accuracy of each measurement on a graph.

Strength of an electromagnet

Combined science

In the Magnets and electromagnets unit, pupils learnt about rules for magnets, magnetic fields of bar magnets, and the properties and uses of electromagnets. 

This unit explores magnetism, including permanent and induced magnets, magnetic fields, and Earth's magnetism. It covers current-induced magnetic effects, electric motors, and devices like microphones and loudspeakers, with an emphasis on models, calculations, and practical applications.

Electromagnetism

Physical activity and equipment requiring safe use

field lines with more arrowheads drawn on them

field lines with fewer arrowheads drawn on them

When field lines are drawn to represent a magnetic field, which of the following represents a region in which the field is stronger?

increasing the number of turns in the coil

spreading the turns of the coil further apart

Which of the following increase the strength of the magnetic field around a coil of wire with a fixed diameter?

directly proportional to the current in its coil.

inversely proportional to the current in its coil.

If all other variables are kept constant, the strength of an electromagnet is always …

The electromagnet is exerting a downwards force on the bar magnet.

The electromagnet is exerting an upwards force on the bar magnet.

The electromagnet and bar magnet have like poles facing each other.

The electromagnet and bar magnet have unlike poles facing each other.

An electromagnet’s strength can be investigated using the apparatus shown. When the electromagnet is switched on, there is a positive mass reading on the balance. Which of the following are correct?

On a graph of experimental results, lines can be drawn through each point to show the accuracy of the two measurements used to plot it. What is the name of these lines?

How many of these graphs show a directly proportional relationship?

Which of the following types of magnet is the magnetic field of an electromagnet most similar to?

A pupil wants to make a strong electromagnet that loses its magnetism completely when switched off. Which of these is a suitable core material? (Note: soft/hard here means magnetically soft/hard.)

Which of the following have a magnetic field around them?

How many newtons are equal to a force of 1 mN?

The mass of a 100 g weight is approximately 1 N.

The mass of a 1 kg weight is approximately 1 N.

The weight of a 100 g mass is approximately 1 N.

The weight of a 1 kg mass is approximately 1 N.

Which of the following statements is correct? (Note: assume the objects are on Earth.)

If $$a$$ increases by 5, then $$b$$ also increases by 5.

The point (0, 0) lies on the graph of $$a$$ against $$b$$.

A graph of $$a$$ against $$b$$ is at an angle of 45° to the $$x$$–axis.

A graph of $$a$$ against $$b$$ is a straight line with a positive gradient.

Two variables, $$a$$ and $$b$$, are directly proportional. Which of the following statements are correct?

Content guidance

Risk assessment required - equipment

Adult supervision required

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Content guidance

Supervision

Worksheet