A model railway controller contains a transformer. The primary coil has 920 turns and is connected to a 230 V alternating supply. The secondary coil has 40 turns and supplies the model railway.
Calculate the output potential difference of the controller.
Use the equation
Vs=VpNsNp\displaystyle V_{\mathrm{s}}=\frac{V_{\mathrm{p}}N_{\mathrm{s}}}{N_{\mathrm{p}}}Vs=NpVpNs
When a train is moving, the current in the secondary coil is 2.3 A.
Assume that no energy is dissipated by the transformer.
Calculate the current drawn by the controller from the supply.
Use the equation
Ip=VsIsVp\displaystyle I_{\mathrm{p}}=\frac{V_{\mathrm{s}}I_{\mathrm{s}}}{V_{\mathrm{p}}}Ip=VpVsIs
The transformer has a soft iron core.
Give one reason why soft iron is suitable for the core.
108 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid, covering 13.2.1 Transformers and induction, 13.2.2 The transformer turns-ratio equation, 13.2.3 The National Grid, 13.2.4 The transformer power equation, and 13.2.5 Advantages of high-voltage transmission. Each one has a worked solution and a mark scheme showing where the marks go.