Three groups of small nails, P, Q and R, are arranged on a bench underneath three electromagnets. One group of nails is copper, one is soft iron and one is steel. Diagram 1 shows what happens when the electromagnets are switched on. Diagram 2 shows what happens when the electromagnets are then switched off. Which row correctly names the materials used for the nails?
- Acopper: P, soft iron: Q, steel: R
- Bcopper: P, soft iron: R, steel: Q
- Ccopper: Q, soft iron: P, steel: R
- Dcopper: Q, soft iron: R, steel: P