Topic P7

Question 1

What direction does the compass needle point to?

Answer 1

In the direction of the magnetic field it’s in

Question 2

What happens when a compass isn’t near a magnet?

Answer 2

It’s needle points north to line up with the Earth’s magnetic field

Question 3

What does the right hand thumb rule do?

Answer 3

Works out the direction of a magnetic field around a current-carrying wire.

Question 4

What two factors does the magnetic field strength depends on:

Answer 4

• Size of current

* Distance from the wire

Question 5

What does twisting a wire into a solenoid do?

Answer 5

Increases the magnetic field strength around the wire.

Question 6

What is an ELECTROMAGNET?

Answer 6

A solenoid with an iron core. It is a magnet that can be turned on and off.

Question 7

What does putting an iron core in a solenoid do?

Answer 7

Increases its magnetic field strength

Question 8

What is a motor effect?

Answer 8

When a magnet and a current-carrying conductor exert a force on each other

Question 9

What three ways can you increase the force on a conductor?

Answer 9

• Increase the current
• Increase the magnetic field strength
• Increase the length of the conductor

Question 10

What is Flemings left hand rule?

Answer 10

Thumb = Force
Index = Magnetic Field
Middle Finger = Current

Question 11

How do electric motors work?

Answer 11

• Direct current is passed through wire

->

• Each side of the coil experiences opposite forces

->

• Coil rotates