(a)[3]
A student brings a soft-iron disc up to the bar and then lets it go. As shown in Fig. 9.1, the disc sticks to the bar. Explain why the soft-iron disc is attracted to the soft-iron bar.
(b(i))[4]
Explain why the bell works when the switch S is opened.
(b(ii))[1]
State and explain whether the bell will operate.