# Electromagnetic Waves

## What type of disturbance creates an electromagnetic (EM) wave?

Electromagnetic waves are created when there is a vibration in an electrical charge. This means that they have a magnetic and electric component.

## What are 2 ways EM waves differ from mechanical waves?

One way that mechanical waves are different than electromagnetic waves is that mechanical waves require a medium to travel through. The other way that these two wave types are different is that electromagnetic waves have a magnetic factor that mechanical waves do not possess.

## The Electromagnetic Spectrum

The electromagnetic spectrum contains different wave types including: radio, microwave, infrared, visible light, ultra-violet, x-ray, and gamma ray.

On the electromagnetic spectrum, radio waves have the longest wavelengths of over 1 mm and the lowest frequency of 30 gigahertz to 300 kilohertz. Its measure of energy is less than 2 x 10^-24 joules which is the lowest on the electromagnetic spectrum. Radio waves are used to transmit television and radio programs.

## Microwaves

Microwaves have the next longest wavelengths which measure at less than 1 decimeter. They have a frequency of between 3 gigahertz and 300 gigahertz. Microwaves contain an energy level of between 2 x 10^-24 and 2 x 10^22 joules. Microwaves can be seen in everyday life when cooking and mobile cell phones.

## Infrared

Infrared waves have wavelengths that measure 710 nm to 1 mm and a frequency of 300 to 400,000 gigahertz. Their energy measures 2 x 10^22 to 3 x 10^-19 joules. Infrared waves are evident in daily life in toasters and grills.

## Visible Light

Visible light waves have wavelengths that measure 380 nanometers to 700 nanometers. Their frequency ranges from 400,000 gigahertz to 0.0075 kilohertz and their energy ranges from 3 x 10-19 to 5 x 10-19 joules. Visible light can be seen in prisms and the world around you.

## Ultraviolet (UV)

Ultraviolet waves' wavelengths reach 10-310 nanometers and their frequencies range from 0.0075 kilohertz to 30,000 terahertz. Their energy ranges from 5 x 10^-19 to 2 x 10^-17 joules. Ultraviolet waves are found in sun tanning beds and security pens.

## X-Ray

The wavelengths of x-rays range from .01 to 10 nanometers. X-rays' frequency ranges from 30,000 terahertz to 30,000,000 terahertz and their energy ranges from 2 x 10^-17 to 2 x 10^-14 joules. X-rays are used to locate and identify breaks or fractures in bones as well as locating cracks or damages in metal components of objects.

## Gamma Rays

With wavelengths measuring less than .01 nanometers and frequencies greater than 30,000,000 terahertz, gamma ray waves can be used to kill cancer cells and sterilize surgical instruments. Their energy measures anything greater than 2 x 10^-14 joules.Gamma rays contain the most energy on the electromagnetic spectrum. They also have the shortest wavelengths and the highest frequency.