Magnets

Question 1

Can magnetic fields travel through solid objects?

Answer 1

Yes

Question 2

What happens to the magnetic field lines when unlike poles come together?

Answer 2

They converge because unlike poles attract

Question 3

What happens to the magnetic field lines when like poles come together?

Answer 3

They diverge because like poles repel

Question 4

What is an electromagnet?

Answer 4

When a current flows through a coil of wire, a magnetic field is produced around the coil. This is an electromagnet.

Question 5

What factors increase the magnetic field strength of an electromagnet?

Answer 5

The coil is wrapped around iron, there are more coils, the voltage is increased

Question 6

What is a motor?

Answer 6

A device that converts electrical energy into kinetic energy

Question 7

What do you need to create a motor?

Answer 7

Electricity and a magnet

Question 8

In Flemings Left Hand Rule, what is the Thumb?

Answer 8

direction of a force/Thrust

Question 9

In Flemings Left Hand Rule, what is the First Finger?

Answer 9

direction of the magnetic Field

Question 10

In Flemings Left Hand Rule, what is the seCond finger?

Answer 10

direction of the Current

Question 11

What things do you need to create movement, or the motor effect?

Answer 11

a current in a wire with a magnetic field

Question 12

What is the motor effect?

Answer 12

When an electromagnet is near a magnet, it feels a force and the wire moves

Question 13

When is there no motor effect of an electromagnet?

Answer 13

If the current is parallel to the magnetic field

Question 14

What increases the size of the motor effect?

Answer 14

Increasing the current, using a stronger magnet

Question 15

What happens in an electric motor?

Answer 15

The motor effect is used to spin a coil of wire

Question 16

What makes the motor turn faster in an electric motor?

Answer 16

The magnetic field or the current increasing

Question 17

What makes the direction of the motor effect change in an electric motor?

Answer 17

The current direction changes, the magnetic field direction changes

Question 18

What is electromagnetic induction?

Answer 18

When a wire in a complete circuit moves across a magnetic field, a voltage is induced across the wire so a current flows in the circuit.

Question 19

For electromagnetic induction to take place, one of two things must move, what are they?

Answer 19

The magnet or the wire

Question 20

In electromagnetic induction, what increases the current?

Answer 20

The magnetic field is stronger, the magnet/coil moves faster, there are more turns on the coil or the coil has a larger diameter.

Question 21

To create electromagnetic induction, what must the coil cut through?

Answer 21

The magnetic field lines

Question 22

How does an electric doorbell work?

Answer 22

1) When the switch is closed, a current flows in the circuit and the electromagnet produces a magnetic field around itself
2) This attracts the metal arm which hits the gong and breaks the circuit
3) The electromagnet loses its magnetism and the metal arm springs back. When the contacts touch, the circuit is complete again. The cycle repeats continuously until the switch is opened.