P7 Magnetism and electromagnetism Flashcards Preview

AQA GCSE Physics > P7 Magnetism and electromagnetism > Flashcards

Flashcards in P7 Magnetism and electromagnetism Deck (21)
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1

If two permanent magnets are brought together North to North what will happen?

They will repel

2

If two permanent magnets are brought together North to South what will happen?

They will attract

3

What is an induced magnet?

An induced magnet is a material that becomes a magnet when it is placed in a magnetic field

4

What force does induced magnetism always produce?

An attraction force between as there induce magnetism is always the opposite way around to the original magnetism (poles are reversed)

5

What happens to an induced magnet when it is removed from the magnetic field causing it?

Once removed from the magnetic field causing it an induced magnet will rapidly lose most / all of its magnetism

6

What is a magnetic field?

It is the area around a magnet where a force acts on another magnet or magnetic material (iron, steel, cobalt, nickel)

7

What is always true about the force between a magnet and a magnetic material?

it is always an force of attraction

8

Where is the force of a magnet strongest?

At the poles

9

What factor affects the strength of a magnetic field?

The distance from the magnet

10

How do you work out the direction of a magnetic field at any point?

The direction of the magnetic field at any point is given by the direction of the force that would act on another north pole placed at that point.

11

Which way do magnetic field lines point?

The direction of a magnetic field line is from the north
(seeking) pole of a magnet to the south(seeking) pole of the magnet.

12

How does a compass work?

The compass needle points in the direction of the
Earth’s magnetic field.

13

How can you plot the magnetic field of a bar magnet using a small compass?

Put the compass at a point by the magnet. Mark the position that the north seeking pole points to and the position that the south seeking pole points to. Then position the compass at each of these new points and repeat until both ends connect to the magnet. Join the field lines from the south (seeking pole) to the north (seeking pole) of the permanent magnet

14

What effect does a current flowing through a wire cause?

When a current flows through a conducting wire a magnetic field is produced around the wire.

15

What two factors affect the strength of an electromagnet?

The strength of the magnetic field depends on the current through the wire and the distance from the wire

16

Why are wires used for electromagnets shaped as coils?

Shaping a wire to form a solenoid increases the strength of the magnetic field created by a current through the wire.

17

What do you know about the magnetic field inside a solenoid?

The magnetic field inside a solenoid is strong and uniform.

18

What effect does adding an iron core have on an electromagnet?

Adding an iron core increases the strength of the
magnetic field of a solenoid.

19

What is an electromagnet?

An electromagnet is a solenoid with an
iron core

20

HT ONLY
What is Flemming's left hand rule?

When a conductor carrying a current is placed in a magnetic field the magnet producing the field and the conductor exert a force on each other. This is called the motor effect. Flemming's left hand rule shows the direction of Motion (thuMb), magnetic Field (First finger) and Current (seCond finger)

21

What is the equation that links force, current, length and magnetic flux density?

f orce = magnetic f lux densit y × current × length