P7 - Magnetism and Electromagnetism

Question 1

What is a ‘solenoid’?

Answer 1

A solenoid is a coil of wire which is used to produce a magnetic field.

Question 2

What is an ‘electromagnet’?

Answer 2

An electromagnet is a solenoid with an iron core.

Question 3

What is the ‘Motor Effect’?

Answer 3

Current carrying conductor is placed in a magnetic field; the conductor and the magnetic producing the magnetic field exert forces on each other; the force produced is the motor effect.

Question 4

What is ‘Fleming’s Left Hand Rule’?

Answer 4

The direction of the force can be found if you know the direction of the current and magnetic field.

Point your index finger in the direction of the magnetic field (N/S).
Point your middle finger in the direction of the current.
Your thumb will be in the direction of the force (motion).

Question 5

How do you go from ‘Milliamps to Amps’ and ‘Kiloamps to Amps’ and vice versa.

Answer 5

Milliamps to Amps -> Divide the value by 1000

Kiloamps to Amps -> Mutiply the value by 1000

Amps to Milliamps -> Mutiply the value by 1000

Amps to Kiloamps -> Divide the value by 1000

Question 6

State number ways of increasing the magnetic field produced by a solenoid.

Answer 6

1. Increasing the current
2. Adding an iron core to the solenoid
3. Increasing the number of turns of wire on the solenoid

Question 7

Describe the magnetic field inside of a solenoid.

Answer 7

The magnetic field inside of a solenoid is similar to the magnetic field of a bar magnet.
Inside of the magnetic field of a solenoid is STRONG and UNIFORM.

Question 8

Generator Effect:

How can you increase the size of the induced potential difference / current?

Answer 8

1. Add more turns of wire on the coil
2. Increase the strength of the magnetic field.
3. Rotate faster / (move the wire more rapidly).

Question 9

What is the ‘Generator Effect’?

Answer 9

When a wire experiences a change in magnetic field a potential difference is induced across the wire - if the ends of the wire are connected to create a full circuit then a current will flow around the circuit.

Question 10

1. Increasing the current through the wire….

2. Increasing the distance from the wire…

Answer 10

1. Increases the magnetic field strength (directly propotional)
2. Decreases the magnetic field strength (inversely proportional)

Question 11

What type of current is induced by a ‘Alternator?’

Answer 11

Alternating Current (A.C)

Question 12

What type of current is induced by a ‘Dynamo’?

Answer 12

Direct Current (D.C)