Magnetism

Question 1

Name four magnetic materials

Answer 1

• iron
• steel
• cobalt
• nickel

Question 2

Why are some materials magnetic?

Answer 2

• contain tiny microscopic domains

Question 3

How are the domains lined up in a strong magnet?

Answer 3

pointing in same direction

Question 4

How are the domains lined up in a demagnetised magnet?

Answer 4

in different directions

Question 5

How can magnets be demagnetised?

Answer 5

• sudden impact

- high temperatures

Question 6

What are soft magnetic materials?

Answer 6

materials which can be easily demagnetised quickly

Question 7

Examples of soft magnetic materials

Answer 7

• iron

Question 8

What are hard magnetic materials?

Answer 8

materials which hold their magnetism for longer

Question 9

Examples of hard magnetic materials

Answer 9

• steel
• cobalt
• nickel

Question 10

Applications of hard magnetic materials

Answer 10

• compass needles

- fridge magnets

Question 11

Applications of soft magnetic materials

Answer 11

• electromagnets - in scrap yards

- transformer core

Question 12

Rules of magnetism

Answer 12

• like poles repel

- unlike poles attract

Question 13

What do field lines show?

Answer 13

the directon of the force produced in the field

Question 14

Direction of field lines

Answer 14

North ➡South

Question 15

How to draw field lines

Answer 15

1. Put magnet in middle of A4 sheet of paper and neatly draw around it with a pencil
2. Place a plotting compass near to the magnet and draw a pencil dot at either end of the needle
3. Move the compass so that one end of the needle points towards the other ends’ dot. Draw another dot
4. Keep on going until you reach the magnet again or the edge of the paper. Join the dots with curved line
5. Add arrowheads, pointing away from north pole and towards the south pole.
6. Start again with the compass in a new position