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Year 11
OCR
Higher

Non-ionising electromagnetic radiations

I can explain the properties, uses and dangers of non–ionising electromagnetic radiation.

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New
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Year 11
OCR
Higher

Non-ionising electromagnetic radiations

I can explain the properties, uses and dangers of non–ionising electromagnetic radiation.

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Lesson details

Key learning points

  1. Radio waves, microwaves, IR and visible light are non–ionising EM radiation. They can harm cells by heating.
  2. Radio waves are produced by oscillations of current. When absorbed, they may produce oscillations of current.
  3. Radio waves and microwaves are used for long distance communication, broadcasting and data transmission.
  4. Microwaves are absorbed by water, so can be used to cook food from within. IR radiation cooks the surface of food.
  5. IR is used for heating and thermal imaging. Visible light and IR are used for data transmission in optical fibres.

Keywords

  • Frequency - The frequency of a wave means the number of oscillations occurring per second, which is the same as the number of waves arriving per second.

  • Non-ionising - Radio waves, microwaves, infrared and visible light are non–ionising electromagnetic waves, as they cannot remove electrons from atoms.

  • Heating - Any process that transfers energy because of a temperature difference, or causes a temperature rise, can be called heating.

  • Oscillations - Oscillations are the vibrations of a wave about a rest position.

  • Antenna - An antenna is a metal structure designed to emit or absorb electromagnetic waves.

Common misconception

The majority of pupils struggle to differentiate between ionising and non–ionising radiation.

Explicitly teach that non–ionising radiation is not able to force electrons off atoms – it cannot turn atoms into ions. What it may be able to do is cause heating by increasing the movement of particles and therefore temperature of the substance.

As a variation to teaching about each type of radiation, pupils could research each one for themselves. This is best done in a structured way, perhaps with an information sheet or table for each one to complete.
Teacher tip

Content guidance

  • Depiction or discussion of sensitive content

Supervision

Adult supervision recommended

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Starter quiz

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6 Questions

Q1.
Which of the following happens when a wave is transmitted by a medium?
The wave bounces off the medium.
Correct answer: The wave passes through the medium.
The wave’s energy is absorbed by the medium.
Q2.
The of a wave is the number of wavelengths per second passing a point.
Correct Answer: frequency
Q3.
Which of the following are examples of ionisation?
A neutral atom gains a proton.
A neutral atom loses two protons.
Correct answer: An neutral atom loses an electron.
Q4.
Which of the following types of electromagnetic radiation has the longest wavelengths?
X-rays
Correct answer: radio waves
light waves
infrared waves
microwaves
Q5.
Which of the following types of electromagnetic radiation can cause ionisation?
radio waves
Correct answer: gamma rays
Correct answer: ultraviolet waves
microwaves
infrared waves
Q6.
Why are some types of electromagnetic radiation more ionising than others?
At longer wavelengths, there is more energy per ‘packet’ of radiation.
Correct answer: At higher frequencies, there is more energy per ‘packet’ of radiation.
At shorter wavelengths, there is less energy per ‘packet’ of radiation.
At lower frequencies, there is more energy per ‘packet’ of radiation.

Exit quiz

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6 Questions

Q1.
Some types of electromagnetic radiation are non-ionising. Which of the following statements about non-ionising radiation are correct?
It includes X-rays.
Correct answer: It includes infrared waves.
It includes gamma rays.
Correct answer: It cannot change the number of electrons an atom has.
Correct answer: It does not cause atoms to become ions.
Q2.
Which of the following is a definition of ‘oscillations’?
The bending of a wave around obstacles.
Correct answer: The vibrations of a wave about a rest position.
Changes in the frequency of a wave over time.
Changes in the charge on an atom when it loses or gains electrons.
Q3.
Which of the following types of radiation is used to communicate between Earth and satellites?
infrared radiation
ultraviolet radiation
Correct answer: microwaves
light waves
X-rays
Q4.
Four types of electromagnetic radiation are: radio waves, microwaves, infrared waves, visible light. How many of these can harm humans, if the intensity is high enough?
none of these
one
two
three
Correct answer: four
Q5.
Lower frequency radio waves and higher frequency radio waves can both be used for long-distance communication. Which of the following describe features of lower frequency radio waves?
Correct answer: They can bend around large objects, such as hills.
The direction in which they travel cannot be changed.
Correct answer: They do not pass through the ionosphere.
They can pass through the ionosphere.
Q6.
Sort the following steps into the correct order to describe the process of sending and receiving a radio signal.
1 - Alternating current causes oscillations of electrons in an aerial.
2 - The oscillations of electrons produces radio waves.
3 - The radio waves are absorbed by an aerial.
4 - Electrons oscillate in an aerial, causing oscillations in an electric circuit.
5 - Electronics convert the signal to produce sound.