P7 - Magnetism And Electromagnetism

Question 1

What is a magnetic field?

Answer 1

The area around a magnet where a magnetic material experienced a force attracting it towards the magnet.

Question 2

What are the 3 magnetic elements?

Answer 2

• Iron
• Nickel
• Cobalt

And steel (which is not an element)

Question 3

What is an induced magnet?

Answer 3

A magnet that is only magnetic when it enters an existing magnetic fired, and stops when it leaves the magnetic field.

Question 4

What is an electromagnet?

Answer 4

A magnet that can be turned in and off.

Needs an electric current in a solenoid (a coil of wire) to work.

Question 5

How to make a magnetic field stronger?

Answer 5

1. Increase current
2. More turns in the wire (coils)
3. Add an iron core
   ~ Will become an induced magnet

Question 6

What are magentic field lines?

Answer 6

Lines that show the shape of a magnetic field

Question 7

What is magnetic flux density?

Answer 7

The “strength” of the magnetic field. (Units: Tesla/T)

Force = magnetic flux density x current x length of wire in magnetic field
F = BIL

Question 8

What is the motor effect?

Answer 8

A wire with a current in it put in a magnetic field will experience a force becuase the magnetic field around the wire is repelled by the magnetic field of the permanent magnetic

Question 9

What is Fleming’s left hand rule?

Answer 9

It tells you the direction of the force

FBI

= thrust of motion (thumb)
= field (index finger)
= current (middle finger)