An electric toothbrush is charged wirelessly by placing it on its charging dock.
When the charging dock is switched on, there is an alternating current (a.c.) in the primary coil located inside the dock. A secondary coil is inside the handle of the toothbrush.
Explain how an electric current is produced in this secondary coil.
The maximum energy stored in the battery of the electric toothbrush is 0.005 kWh.
Show that this maximum energy is 1.8 × 104 J.
The charging dock has a useful output power of 2.5 W. The manufacturer claims that the battery can be charged to 60% capacity in less than 90 minutes90\text{ minutes}90 minutes.
Show that this claim is true.
35 exam-style questions on CIE IGCSE Physics 4.5.1a Electromagnetic induction. Each one has a worked solution and a mark scheme showing where the marks go.