Magnetism

Question 1

What causes a magnetic field?

Answer 1

Originate as a result of moving charges. The clockwise or anticlockwise spin of an electron creates a magnetic field perpendicular to its direction of motion

Question 2

Properties of magnetic field lines

Answer 2

• Closer the field lines at a point, greater the field at that point
• Arrows indicate direction of the field
• Arrow points point from N to S
• Lines never cross

Question 3

Compare the magnetic field of the Earth to the magnetic field of a bar magnet

Answer 3

The Earth’s core is made up of magnetic materials which causes the earth to have magnetic properties. Therefore the Earth’s magnetic field is like a giant bar magnet, with a magnetic N and S pole.

Question 4

How does a compass indicate the direction of a magnetic field?

Answer 4

A compass is a magnet. When placed at any position in the earth’s magnetic field, it will come to rest with the N pole of the compass pointing in the direction of magnetic north.

Question 5

How is the Aurora Borealis formed?

Answer 5

1. Charged particles from solar winds pass through the ionosphere at the polar regions of the earth’s magnetic field.
2. They collide with the atoms and molecules of gases, Nitrogen and Oxygen.
3. These gas molecules obtain energy and start to glow, results in colourful pattern of red, green, blue and purple light in sky.