7: Magnetism and Electromagnetism

Question 1

Alternator:

Answer 1

A device that makes use of the generator effect to generate alternating current.

Question 2

Attraction:

Answer 2

Opposite poles will experience a force of attraction, meaning they will experience a force towards each other. The force between a magnet and magnetic material is always one of attraction.

Question 3

Current-Carrying Wires:

Answer 3

When current flows through a wire, a magnetic field is generated around it. The strength of the field is dependent on the magnitude of the current and the distance from the wire.

Question 4

Dynamo:

Answer 4

A device that makes use of the generator effect to generate direct current.

Question 5

Electric Motor:

Answer 5

A current-carrying coil of wire in a magnetic field. The two sides of the coil that are perpendicular to the magnetic field experience forces in opposite directions, causing rotation.

Question 6

Electromagnet:

Answer 6

A solenoid with an iron core.

Question 7

Fleming’s Left-Hand Rule:

Answer 7

A rule used to determine the orientation of the force (thumb), current (second finger) and magnetic field (first finger) when a current carrying wire is placed in a magnetic field (motor effect).

Question 8

Generator Effect:

Answer 8

When there is relative motion between an electrical conductor and a magnetic field, a potential difference will be induced across the ends of the conductor. A current will flow if this conductor is part of a complete circuit.

Question 9

Induced Magnet:

Answer 9

A material that becomes a magnet when it is placed in an existing magnetic field, but loses its magnetism quickly once it is removed. Induced magnetism always produces attractive forces

Question 10

Magnetic Compass:

Answer 10

A device containing a small bar magnet that points in the direction of the Earth’s magnetic field.

Question 11

Magnetic Field Lines:

Answer 11

Lines representing the strength and direction of a magnetic field. The field line direction at any point is in the direction that a force would act on another north pole if placed at that point.

Question 12

Magnetic Field:

Answer 12

The region around a magnet in which another magnet or magnetic material will experience a force.

Question 13

Magnetic Materials:

Answer 13

Iron, steel, cobalt and nickel.

Question 14

Magnetic Poles:

Answer 14

The regions of a magnet where the magnetic forces are at their strongest.

Question 15

Microphone:

Answer 15

A device that uses the generator effect to convert the pressure variations of sound waves into variations in the electrical current of a circuit.

Question 16

Motor Effect:

Answer 16

When a current-carrying wire is placed in a magnetic field, a force will be experienced between the wire and the magnet responsible for the field.

Question 17

Permanent Magnet:

Answer 17

A magnet that produces its own magnetic field.

Question 18

Repulsion:

Answer 18

Like-poles will experience a force of repulsion, meaning they will experience forces in opposite directions.

Question 19

Solenoid:

Answer 19

A wire wrapped into the shape of a coil, that has a strong and uniform magnetic field inside of it. The solenoid’s magnetic field strength can be increased by adding an iron core.

Question 20

Step-Down Transformer:

Answer 20

A transformer that has a smaller potential difference in the secondary coil than in the primary core.

Question 21

Step-Up Transformer:

Answer 21

A transformer that has a larger potential difference in the secondary coil than in the primary core.

Question 22

Tesla:

Answer 22

The unit of magnetic flux density.

Question 23

Transformer:

Answer 23

An iron core with a primary and secondary coil of wire wound around opposite ends.