P12 - Electromagnetic Waves

Question 1

What are electromagnetic waves?

Answer 1

Electric and magnetic disturbances that can be used to transmit energy from a source to an absorbed.

Question 2

What do electromagnetic waves transfer?

Answer 2

They do not transfer matter but only energy. They have different wavelengths for a different amount of energy.

Question 3

What is the order of the spectrum?

Answer 3

Radio waves
Microwaves
Infrared radiation
Visible light
Ultraviolet
X rays
Gamma rays

Question 4

Which way along the electromagnetic spectrum does wavelength increase?

Answer 4

Gamma rays have the shortest wavelengths and radio waves have the longest.

Question 5

What is the speed of an electromagnetic wave?

Answer 5

3 * 10 power of 8 m/s through a vacuum.

Question 6

What is the equation for wave speed?

Answer 6

Wave speed (m/s) = frequency (hertz) * wavelength (m)

Question 7

As all electromagnetic waves have the same speed what is the difference?

Answer 7

The shorter the wavelength, the higher the frequency. Energy of the wave increases as the frequency increases. Gamma rays have highest energy and frequency but lowest wavelength.

Question 8

What is light from lamps and the sun called?

Answer 8

White light

Question 9

How does wavelength change within visible light?

Answer 9

The wavelength increases across the spectrum from violet to red.

Question 10

What is infrared radiation?

Answer 10

All objects emit it. The hotter an object, the more it emits. It is absorbed by your skin.

Question 11

What are the dangers of infrared radiation?

Answer 11

It can damage, burn or kill skin cells as it heats them up.

Question 12

What are infrared devices?

Answer 12

Optical fibers in communications systems use infrared as it is absorbed less than visible light by the glass fibers.

Question 13

Examples of infrared

Answer 13

Remote controls.
Infrared scanners in medicine to detect unhealthy tissue.
Infrared cameras to see in the dark.
Electric heaters.
Electric cookers.

Question 14

What are microwaves used for?

Answer 14

Communication is satellite TV we they can pass through the atmosphere and reach satellites.
Mobile phone signals.
Microwave ovens as they penetrate water molecules heating them.

Question 15

What are radio waves used for?

Answer 15

Carry radio.
TV signals.
Phone signals.
Connect a computer to printer.
Can penetrate and heat bodies