Magnetism and Electromagnetism

Question 1

Magnetic field

Answer 1

The region around a magnet where a force acts on another magnet or on a magnetic material (iron, steel, cobalt and nickel).

Question 2

Attraction

Answer 2

The force between a magnet and a magnetic material is always one of attraction.

Question 3

Magnet

Answer 3

A magnet is an object or a device that gives off an external magnetic field.

Question 4

Induced magnetism

Answer 4

When a piece of unmagnetised magnetic material is placed in the magnetic field of a permanent magnet, it becomes a magnet itself.

Question 5

The force rule for two magnetic poles near eachother

Answer 5

Like poles repel, unlike poles attract.

Question 6

Where the magnetic fields are strongest

Answer 6

At the poles of the magnet.

Question 7

Permanent magnet

Answer 7

Materials that are constant magnets.

Question 8

Plotting compass

Answer 8

Small magnetic compass used to detect magnetic fields.

Question 9

Electromagnets

Answer 9

Magnets created by electricity e.g school bell.

Question 10

Solenoids

Answer 10

A long coil of insulated wire.

Question 11

How solenoids are used

Answer 11

Used in lots of devices where a strong magnetic field needs to be produced.

Question 12

The characteristics of the magnetic field inside a solenoid

Answer 12

Strong and uniform.

Question 13

The characteristics of the magnetic field around a solenoid

Answer 13

Has a similar shape to that of a bar magnet.

Question 14

Electromagnetic induction

Answer 14

The production of a potential difference (voltage) when a conductor, such as a wire, is moved through a magnetic field or exposed to a varying magnetic field. If the conductor is part of an electric circuit, an induced current will flow.

Question 15

Current

Answer 15

Moving electric charges, e.g. electrons moving through a metal wire.

Question 16

Voltage

Answer 16

The potential difference across a cell, electrical supply or electrical component. It is measured in volts (V).

Question 17

Fleming’s left hand rule

Answer 17

Shows which way a current-carrying wire tries to move when placed in a magnetic field - First finger shows Field, seCond finger shows Current, thuMb shows Movement.

Question 18

Motor effect

Answer 18

When a conductor using a current is placed in a magnetic field, the magnet producing the field and the conductor exert a force on each other.

Question 19

Equation for power (when referring to electrical energy).

Answer 19

Power = voltage x current

Question 20

The equation for calculating the force on a wire

Answer 20

Force (N) = magnetic flux density (T) × current (A) × length (m)

Question 21

Magnetic flux density

Answer 21

This is the amount of flux passing through an unit area at a right angle to the magnetic field lines.

Question 22

Generator

Answer 22

Device that converts kinetic energy into electrical energy.

Question 23

Induce

Answer 23

To cause something or make it happen. A potential difference is caused or induced when a coil of wire moves in a magnetic field.

Question 24

Pole

Answer 24

Either of the two points of a magnet to and from which the lines of magnetic force are directed.

Question 25

What magnetic flux density is measured in

Answer 25

Tesla (T)