Magnets

Which one of the following statements is true of magnets?

• All metals are attracted to magnets.

• Like poles of magnets can repel each other.

• Two magnets will always attract each other.

• Larger magnets have greater magnetic pull than smaller magnets.

Jan suspended four identical bar magnets from the ceiling using strips at positions A, B, C and D. she placed a tray of iron nails below the magnets as shown below. It was observed that some nails were attracted to the magnets.

Based only on the results of the experiment above, which magnet has the weakest magnetic pull?

• A

• B

• C

• D

Lena conducted an experiment using the electromagnet shown below. An object H, was attached to a toy car. The toy car was first placed 4cm away from the iron nail. It was then observed that the toy car moved away from the iron nail. Why did this happen?

• When electricity flowed through the wire, it made the iron nail a magnet and repelled H, which is also a magnet.

• When electricity flowed through the wire, it made the iron nail a magnet and repelled H, which is a magnetic material.

• The wooden table is smooth and the wheels rolled the car away.

• When electricity flowed through the wire, it made the iron nail a magnet and attracted H, which is a magnetic material.

The diagram shows a horseshoe magnet. If the magnet is placed in a box of paper clips, which part of the magnet A, B, C or D will attract the most number of paper clips?

• A

• B

• C

• D

Study the classification chart. Based on the information given, which of the following is correct?

• X - copper, Y - aluminium, Z - iron

• X - paper, Y - copper, Z - aluminium

• X - rubber, Y - gold, Z - steel

• X - cotton, Y - steel, Z - copper

Ann carried out an experiment on three objects with a magnet. She wanted to find out how the objects would respond when both the poles of the magnet are placed near them. The diagram shows her results. What could objects A, B and C be?

• A - magnet, B - ice cream stick, C - iron pin

• A - iron pin, B - magnet, C - handkerchief

• A - iron pin, B - ice cream stick, C - magnet

• A - ice cream stick, B - iron pin, C - magnet

Roger placed two cubes, A and B, on a bar magnet as shown in the diagram.

He then lifted up the bar magnet but cube B immediately dropped off. Roger wrote down some possible conclusions from his experiment. Which of the following conclusion(s) is/are possible?

A: Cube A is magnetic.

B: Cube B repels the bar magnet.

C: Cube B is made of a non-magnetic material.

• A and B only

• B and C only

• A and C only

• A, B and C

Gina brought a magnet near a metal paper clip. She observed that the paper clip was attracted to the magnet when it was still 5 cm away. Based on her observation, which of the following conclusions can Gina make?

• Magnetic force can act at a distance.

• The North pole of a magnet is the strongest.

• The paper clip is made of a non-magnetic material.

• Only the North pole of a magnet can attract a magnetic object at a distance.

The diagram shows a door stopper. Part A is made of a magnetic material. Which of the following statements best explains how a door stopper keeps a door open?

• The magnet repels part A.

• The magnet attracts part A.

• Part A is made from aluminium.

• The magnet needs electricity to attract part A.

John uses a magnet to hold a note on a door as shown in the diagram. What could be the materials used to make the magnet and the door?

• Magnet - iron, Door - copper

• Magnet - steel, Door - iron

• Magnet - clay, Door - steel

• Magnet - aluminium, Door - wood