Practise applying Faraday’s law to induced e.m.f. magnitude and Lenz’s law to direction, calculating flux change, time or turns and interpreting the negative sign.
A square coil of wire of side length 12 cm consists of 8 insulated turns. The coil is stationary in a uniform magnetic field. The plane of the coil is perpendicular to the magnetic field, as shown in Fig. 6.1.
Fig. 6.1
The flux density B of the magnetic field varies with time t as shown in Fig. 6.2.
Fig. 6.2
State how Fig. 6.2 shows that the electromotive force (e.m.f.) E induced across the terminals between t=0 and is constant.
Calculate the magnitude of E.
The procedure in (b) is repeated, but this time the terminals of the coil are connected together.
State and explain the effect on the coil of connecting the terminals together during the change of magnetic flux density shown in Fig. 6.2.