(a)[1]
State the substance used for the transformer core.
(b)[3]
A current in the primary coil creates a magnetic field in the core. Explain how an alternating voltage is produced in the secondary coil.
(c)[2]
The transformer has $4600$ turns on the primary coil and is connected to a mains supply of $230\,\text{V}$. An output of $5.0\,\text{V}$ is used to operate the bell. Calculate the number of turns needed on the secondary coil.
(d)[1]
State one modification that can be made to the transformer shown in Fig. 8.1 so that it can be used as a step-up transformer.