Electromagnetic waves

What type of wave are electromagnetic waves?

Transverse

What do electromagnetic waves do?

Transfer energy from the source of the waves to an absorber

What is one example of electromagnetic waves?

Light

What colour has the lowest frequency and longest wavelength?

Red

What colour has the highest frequency and shortest wavelength?

Violet

What are the two different types of visible light reflection?

• Specular reflection

• Diffuse reflection

Specular reflection causes light to reflect…

Neatly e.g in a mirror

Diffuse reflection causes light to reflect…

Scattered e.g on the ocean

Which type of light reflection produces an image?

Specular

What is the acronym useful for remembering the electromagnetic spectrum?

Raw meat is very unsanitary Xcept giraffe

What is the order of the electromagnetic spectrum?

(Lowest frequency to highest)

1. Radio waves

2. Microwaves

3. Infrared

4. Visible light

5. Ultraviolet

6. X-rays

7. Gamma rays

Electromagnetic waves do not need…

A medium to travel in.

This means they can travel through vacuums

All electromagnetic waves travel at __ in a vacuum

300,000,000 m/s

How are radio waves produced?

When electrons oscillate in electrical circuits

What are some things that use radio waves?

• TV

• Radio

• Mobile phones

What are some things that use microwaves?

• Microwave ovens

• Satellites

• Mobile phones

What are some things that use infrared waves?

• Heaters

• Iron grills

• Toasters

What is the danger of infrared?

It can damage skin cells when exposed or touching for too long

What are some things that use visible light waves?

• LED lights

• Lasers

What are some things that use ultraviolet waves?

• The sun

• Very hot objects

What are the dangers of ultraviolet waves?

• Increase the risk of skin cancer

• Can cause skin to age prematurely

What are some things that use X-ray waves?

X-rays

What are the dangers of X-rays?

• Increases risk of cancer

• Can cause mutations

Where do gamma rays come from?

Radioactive substances

What are the dangers of gamma rays?

• They can pass through the human body and cause ionisations that damage tissue and DNA

• Increase the risk of cancer