A primary coil is placed close to a secondary coil. The secondary coil is connected to a centre-zero ammeter. The primary coil is connected to a power supply and a switch. The table shows the secondary ammeter reading at three stages of an investigation.
| Stage | Secondary ammeter reading |
|---|---|
| The switch is closed | Brief deflection to the right |
| The switch remains closed | Zero |
| The switch is opened | Brief deflection to the left |
Explain why the ammeter reading is zero while the switch remains closed.
State what the table shows about the direction of the induced current when the switch is closed and opened. Give a reason for this.
State how the peak induced current in the secondary coil would change if the current in the primary coil increased more quickly when the switch was closed. Give a reason for your answer.
92 exam-style questions on Edexcel GCSE Physics 13.1 Inducing a current, covering 13.1.1 Producing an electric current by induction, 13.1.2 Factors affecting the induced potential difference, 13.1.3 Alternators and dynamos, and 13.1.4 Microphones and loudspeakers. Each one has a worked solution and a mark scheme showing where the marks go.