1. 1
   A scrapyard worker is sorting mixed metal waste by holding a strong permanent magnet above a conveyor belt to remove magnetic scrap before the rest is recycled.

   (a)

   Which material on the belt would be lifted by the magnet?

   [1 mark]

   • AA plastic bottle
   • BAn aluminium can
   • CA copper pipe
   • DAn iron nail

   (b)

   The worker notices that after the iron nail has been near the magnet for some time, it can itself weakly attract small steel pins, but it loses this ability soon after being moved away. What does this show about the nail?

   [1 mark]

   • AThe nail has become a permanent magnet
   • BThe nail has lost its magnetic properties completely
   • CThe nail has become an electromagnet
   • DThe nail has had magnetism induced in it temporarily

   (c)

   Explain what is meant by induced magnetism, and state why the iron nail is suitable for showing this effect rather than a piece of steel.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A geography student uses a plotting compass placed near a bar magnet to trace the shape and strength of its magnetic field for a school project.

   (a)

   At any point near the magnet, in which direction does the compass needle point?

   [1 mark]

   • ARandomly, since field direction cannot be measured with a compass
   • BAlways directly towards the magnet's centre
   • CIn the direction of the force on a S pole placed at that point
   • DIn the direction of the force on a N pole placed at that point

   (b)

   The student notices the field lines are much closer together near the poles of the magnet than further away. What does this show?

   [1 mark]

   • AThe magnetic field is weaker where the lines are closer together
   • BThe spacing of field lines has no relation to field strength
   • CThe magnetic field direction reverses where lines are closer together
   • DThe magnetic field is stronger where the lines are closer together

   (c)

   Describe how the student could use the plotting compass to trace and record the pattern of the magnetic field lines around the whole bar magnet.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A toy designer is developing a novelty fridge magnet set that includes both a permanent steel magnet and a temporary soft iron keeper bar, and wants to demonstrate the magnetic field pattern to customers in store.

   (a)

   State three differences between the properties of the permanent magnet and the temporary magnet in this set.

   [3 marks]

   (b)

   Describe an experiment, using iron filings, that the designer could perform to show the pattern of the magnetic field around the steel bar magnet, and explain how the pattern would appear different, or absent, if a small unmagnetised steel bar were tested in the same way.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A recycling plant uses a large electromagnet, rather than a permanent magnet, suspended from a crane to lift and sort scrap iron and steel from a mixed waste pile, releasing the material into a separate skip when needed.

   (a)

   Explain, in terms of magnetic fields, forces between poles, and magnetised and unmagnetised materials, why an electromagnet is more suitable than a permanent magnet for this task, and describe how the plant operator could increase or decrease the strength of the lifting field.

   [6 marks]

   (b)

   During testing, an engineer places a small unmagnetised steel bar and a small soft iron bar side by side directly beneath the switched-on electromagnet, and then switches the electromagnet off. Explain what happens to each bar while the electromagnet is on and after it is switched off, referring to induced magnetism, magnetic and non-magnetic materials, and the differences between temporary and permanent magnetic behaviour.

   [6 marks]

   Total for question 4: 12 marks

End of questions