Electromagnetic Energy

Fields and how electricity is produced and transmitted, and the uses of the electromagnetic spectrum.

8 questions, free, marked as you go with a worked explanation on every one.

What this covers

• induction and power transmission

The questions

1. A radio wave has a frequency of 1.0 × 10⁸ Hz. What is its wavelength? Use c = 3.00 × 10⁸ m/s.
2. What is induced when a conductor moves through a magnetic field?
3. Why is electricity transmitted over long distances at very high voltage?
4. Which are applications of the electromagnetic spectrum? Select all that apply.
5. Which type of electromagnetic radiation carries the most energy per photon?
6. How does a transformer change voltage?
7. A pole-mounted transformer steps the 7200 V carried on a distribution line down to the 240 V supplied to a house. Its primary coil has 3000 turns. How many turns does the secondary coil have?
8. A microwave oven and a dental X-ray machine both emit electromagnetic radiation, yet only the X-rays are described as ionising. What accounts for the difference?

Answer these free