This question is about waves in the electromagnetic (e.m.) spectrum - Edexcel - GCSE Physics: Combined Science - Question 6 - 2022 - Paper 1

To find the wavelength ( λ ) of the microwaves, we can use the formula:

λ = rac{v}{f}

Where:

• v = speed of light = 3.00 × 10^8 m/s
• f = frequency = 2.45 × 10^9 Hz (since 1 GHz = $10^9$ Hz)

Substituting in the values, we get:

λ = rac{3.00 imes 10^8 ext{ m/s}}{2.45 imes 10^9 ext{ Hz}} = 0.122 ext{ m}

Thus, the wavelength of the microwaves is 0.122 m.

The efficiency of the microwave oven is 55%, and it transfers 42,000 J of energy. To find the total energy supplied ( E_{total} ), we can use the formula:

E_{total} = rac{E_{supplied}}{Efficiency} = rac{42000 ext{ J}}{0.55}

Calculating this, we find:

$$E_{total} eq 76363.63 ext{ J}$$

Thus, the total amount of energy that must be supplied to the oven is approximately 76,364 J.

X-rays and radio waves are part of the electromagnetic spectrum but serve different purposes:

Uses of Both Types of Radiation

• X-rays:

  • Medical diagnosis, such as imaging broken bones and detecting lung issues.
  • Treatment of cancer through targeted radiation therapies.
  • Enhancing airport security through luggage scanning.
  • Art restoration by revealing underlying layers.

• Radio Waves:

  • Used in broadcasting television and radio.
  • Fundamental for communications, allowing for mobile and wireless data transfer.
  • Essential in various technologies like satellite transmission and remote controls.

Different Ways Electrons are Involved

• X-rays:

  • Produced when electrons drop from higher energy levels to lower ones within an atom, releasing energy as high-frequency radiation.

• Radio Waves:

  • Generated by oscillating electrical currents in circuits, where the charge movement creates waves corresponding to their oscillation frequency.