Fig. 9.1 illustrates a wireless charging plate that is used to charge the battery in a mobile phone (cell phone). The wire coil is part of an electric circuit. The charging plate is linked to an a.c. power supply, and the power supply is switched on.
(a)[2]
Describe the magnetic field around the charging plate in terms of its magnitude and direction.
(b(i))[2]
Explain why a current flows in the secondary coil shown in Fig. 9.2.
(b(ii))[1]
Suggest why the transformer made from the charging plate and mobile phone is not $100\%$ efficient.
(c(i))[2]
Calculate the time taken to fully recharge a completely uncharged battery.
(c(ii))[2]
Calculate the charge flowing through the battery in $60\,\text{s}$.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Magnetic field magnitude is continuously changing” …