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Light and the Electromagnetic Spectrum

Uses of electromagnetic radiation

  • 3 things to know
  • Paper 1

Overview

Uses of radio waves, microwaves, infrared, visible light, ultraviolet, X-rays and gamma rays, from broadcasting, satellite links, cooking and thermal imaging to optical fibres, security marking, disinfecting water, medical images, sterilising and cancer treatment.

What you need to know

Answer each one before you reveal it.

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Key term

Explain how a microwave oven cooks food.

Key term

State the use of infrared that allows information to be carried over long distances.

Key term

Give three uses of visible light.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Give two uses of radio waves.

    Model answer

    Broadcasting radio and television programmes, and communications including satellite transmissions.

  2. 2

    Explain why radio waves are chosen for broadcasting over long distances.

    Model answer

    They travel long distances through the atmosphere without being strongly absorbed.

  3. 3

    Give two uses of microwaves.

    Model answer

    Cooking food, and communications including satellite transmissions.

  4. 4

    Explain why microwaves are used for satellite communications.

    Model answer

    They pass through the atmosphere without being absorbed much, so they can reach a satellite and return.

  5. 5

    Explain how a microwave oven cooks food.

    Model answer

    The microwaves are absorbed by water in the food, transferring energy that heats the food throughout.

  6. 6

    Give three uses of infrared radiation.

    Model answer

    Cooking with grills, thermal imaging, and short range communications such as television remote controls.

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