Three plotting compasses are placed in the magnetic field of a bar magnet. The circles in Figure 4.1 show the positions of the plotting compasses. State the effect that a magnetic field has on a magnetic pole.

a bar magnet with N at its left end and S at its right, an empty circle labelled 1 to the left of the N pole and empty circles labelled 2 and 3 below the middle of the magnet, marking the plotting-compass positions

4(b)Magnetic Fields Magnetic MaterialsEasy2 marks

Figure 4.2 shows an arrow that represents the needle in a plotting compass. The needle points in the direction of the magnetic field. On Figure 4.1, draw an arrow in each numbered circle to show the direction in which the compass needles point.

a plotting compass drawn as a circle with a single arrow inside it pointing straight up

Draw with the mouse or a finger.

4(c)Magnetic Fields Magnetic MaterialsEasy1 mark

State how the magnetic field at circle 3 is different from the magnetic field at circle 2.

4(d)Electromagnetic Induction GeneratorsEasy3 marks

The bar magnet is moved into a coil of wire as shown in Figure 4.3.

a bar magnet, N pole leading, being pushed into a coil of wire whose ends are joined in a closed loop

Complete the sentences to explain what happens. As the magnet moves into the coil, the coil experiences a changing magnetic field.

An e.m.f. is in the coil. This causes a in the coil which produces a magnetic field around the coil. The magnetic field opposes .