# What is the Electromagnetic Spectrum?

Updated on April 1, 2014

## What are the essential points I need to know?

Did you know that electromagnetic waves are the vibrations of electric and magnetic fields? This means that they don't need anything to travel around. Visible light waves are a classic example of this, as they have travelled from the sun which is millions of miles away!

Radio waves have the longest wavelength and lowest frequency in the spectrum, whereas gamma rays have the shortest wavelength and the highest frequency in the spectrum. We can only see a small proportion of the electromagnetic spectrum, which is visible light. There are seven types of waves in the electromagnetic spectrum, each which have their own properties. In the table below, there are all the electromagnetic waves in the spectrum.

## Electromagnetic Wave Summary Table

Electromagnetic Wave
Wavelength (m)
Frequency (Hz)
Uses
10^3
3x10^5
Communication
Microwaves
10^-2
3x10^10
Communication, microwave
Infrared waves
10^-5
3x10^13
Communication, toasters, grills
Visible light waves
5x10^-6
6x10^13
Communications, laser light
Ultraviolet waves
10^-8
3x10^16
Tanning beds, detecting forged bank notes
X-rays
10^-10
3x10^18
Medical, security
Gamma rays
10^-12
3x10^20
Medical, food industry

Radio waves have the longest wavelength in the electromagnetic spectrum and the lowest frequency. Radio waves can be from a few km big to a few metres. Radio waves are usually used for communications like your car stereo. The radio in your car picks up radio waves, that is why we can hear the radio station that is playing.

## Microwaves

Microwaves are the second longest wave in the electromagnetic spectrum, but these waves are measured in centimetres. The longest and most useful length of microwave is the foot long one, as it is used in our microwaves for heating food up. Microwaves are also used for viewing the earth from space as they can penetrate most materials. They are also used in radar systems like forecasting the weather and they are also used in communications as they can penetrate almost anything.

## Infrared Waves

Infrared waves are very useful to us. Not only is it the third wave in the electromagnetic spectrum, infrared waves are also used for communications and cooking. They have wavelengths in the region of 1 millimetre to about 750 nanometres. Infrared waves are in toasters and grills, which means you can cook your food with them. Infrared waves can also be used in burgular alarms, mobile phones and most commonly in remote controls. So when you switch on your TV the next time, just think that infrared waves are communicating with the sensor in the TV to switch it on!

## Visible Light Waves

Visible light waves are the only part of the electromagnetic spectrum, which we can see as the colours in the rainbow. Their wavelength is roughly 380 nanometres to 740 nanometres. Our primary and source of light is the sun, but artificial light like light bulbs also can produce light waves. Light waves are used in communications such as fibre optic cables. Light waves are also very useful to plants, as they can photosynthesise with light waves to produce oxygen and glucose from carbon dioxide and water. Although, strong light to the eye can cause blindness.

## Ultraviolet Waves

Ultraviolet waves are used in many places in our every day lives. For example, if you pop down to the bank they will scan over your bank note with a UV light to make sure it isn't forged. Also many people use UV waves to tan themselves, whether they use a tanning bed or tan naturally in the sun it doesn't matter. However, too much UV rays can burn your skin and increase your chance of getting cancer. Furthermore, UV light is used in the dentist industry in many diiferent ways like hardening brace glue to teeth. Ultraviolet waves have wavelengths between 10 and 380 nanometres.

## X-rays

X-rays are most often used in the medical industry, but can also be used in the security industry as well. Their wavelengths are between 10 and 0.01 nanometres. Their use in the medical industry is really useful, as they can detect broken bones and other various medical conditions. This can then be used to treat your medical condition better. Moreover, in the security industry they can be used to detect items inside of people trying to smuggle things into or out of the country.

## Gamma Rays

Gamma rays have the shortest wavelength in the electromagnetic spectrum and the highest frequency. Their wavelength is less than 10 picometres. Gamma rays are starting to be used in medicine as they can penetrate the body with ease. This could lead to new cancer treatment and hopefully saving more lives. Also gamma rays are used in the food industry to seal cans and make sure the environment in the can is sterile so the food doesn't go off. The dosage is only very small so it will not affect you in anyway.

See results

## How can I remember all the waves in the electromagnetic spectrum?

There is a very unique acronym I was taught which goes as follows; randy men in leather underwear excite gays. Now in practice this looks like this:

• Microwaves
• Infrared Waves
• Visible Light Waves
• Ultraviolet Waves
• X-rays
• Gamma Rays

If you can come up with any of your own, comment it in the comments box and I will add it to the list if you would like it to be on the list.

Other science articles you may like:

What are Alkanes?

What are Alkenes?

16

0

7

0

26

2

9