What are the parts of the electromagnetic spectrum, and what are their uses and dangers?
The order of the electromagnetic spectrum from radio waves to gamma rays, the shared properties of EM waves, and the uses and dangers of each region.
A CCEA GCSE Double Award Science (Physics Unit P2) answer on the order of the electromagnetic spectrum from radio waves to gamma rays, the properties shared by all electromagnetic waves, and the main uses and dangers of each region.
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What this dot point is asking
CCEA Double Award wants you to recall the order of the electromagnetic spectrum, the shared properties of all electromagnetic waves, and the uses and dangers of each region. Listing the spectrum in order and matching uses to regions are very common questions.
The order of the spectrum
Visible light is only a thin band in the middle of the spectrum, running from red (lowest frequency) to violet (highest frequency).
Shared properties
Across the spectrum, as frequency increases the wavelength decreases (because with fixed), and the energy carried increases.
Uses and dangers
Examples in context
- Example 1. A TV remote
- A remote control sends infrared pulses to the television, a use of infrared for short-range signalling.
- Example 2. A microwave oven
- Microwaves are absorbed by water molecules in food, making them vibrate and heat the food from within, which is faster than the surface heating of an infrared grill.
- Example 3. Sterilising medical kit
- Gamma rays are used to kill bacteria on sealed surgical instruments because they penetrate the packaging and damage the cells of any microorganisms inside.
- Example 4. A TV satellite dish
- Microwaves carry television signals up to a satellite and back down to a dish, because they pass easily through the atmosphere and can be sent in a narrow beam over very long distances.
Try this
Q1. Which region of the spectrum has the highest frequency? [1 mark]
- Cue. Gamma rays.
Q2. State one property shared by all electromagnetic waves. [1 mark]
- Cue. Any of: transverse, travel at the same speed in a vacuum, transfer energy.
Q3. Give one use of microwaves and one use of X-rays. [2 marks]
- Cue. Microwaves: cooking or communication. X-rays: medical imaging of bones or security scanning.
Exam-style practice questions
Practice questions written in the style of CCEA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
CCEA-style3 marksList the seven regions of the electromagnetic spectrum in order of increasing frequency.Show worked answer →
In order of increasing frequency (and decreasing wavelength):
radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.
Markers reward the correct order, starting from radio waves (lowest frequency) and ending with gamma rays (highest frequency).
CCEA-style4 marksGive one use and one danger of ultraviolet radiation, and one use of microwaves.Show worked answer →
Ultraviolet use: security marking, detecting forged banknotes, sterilising water, or sun tanning.
Ultraviolet danger: it can damage skin cells and cause skin cancer, and can damage the eyes.
Microwaves use: cooking food, or mobile phone and satellite communication.
Markers reward a valid use of ultraviolet, a valid danger of ultraviolet, and a valid use of microwaves.
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Sources & how we know this
- CCEA GCSE Science Double Award specification — CCEA (2017)