(a)[2]
State Faraday’s law governing electromagnetic induction.
(b)
Two coils are wound on an iron bar, as shown in Fig. 7.1. Coil 1 is connected to a potential difference (p.d.) $V_1$, which creates a magnetic field in the iron bar. Fig. 7.2 shows how the magnetic flux density $B$ in the iron bar varies with time $t$. A voltmeter measures the electromotive force (e.m.f.) $V_2$ induced across coil 2.
(c(i))[3]
The switch is now closed. As it is closed, the copper ring is seen to jump upwards. Explain why this occurs.
(c(ii))[1]
Suggest, with a reason, what effect would result if the procedure in (c)(i) were repeated with the cell terminals reversed.