A wireless charging pad for a smartphone contains a primary coil that transfers energy magnetically to a secondary coil inside the phone. This wireless charging setup acts as a transformer that reduces voltage.
Name the type of transformer that reduces voltage.
Explain why the transformer core is made of a soft magnetic material, such as iron.
State the equation linking primary voltage, secondary voltage, and the turns ratio.
The transformer inside the charger has 480 primary turns and 24 secondary turns. The input voltage to the primary coil is 120 V. Calculate the output voltage on the secondary coil.
The alternating current used in the wireless pad has a frequency of 110,000 Hz. The charger vibrates at this same frequency. Explain why these vibrations cannot be heard by a human.
A status indicator in the smartphone pulses regularly. There is a pulse every 2.5 ms. Calculate the frequency of these pulses.
20 exam-style questions on Edexcel IGCSE Physics Electromagnetic induction. Each one has a worked solution and a mark scheme showing where the marks go.