Topic 8-The Electromagnetic Spectrum

Question 0

What are the different parts of the electromagnetic spectrum?

Answer 0

The different part of the electromagnetic spectrum have different wavelengths and frequencies, and energies. The higher the frequency of the wave, the higher it’s energy. The frequency, wavelength and energy of an electromagnetic wave completely determine it’s properties and how it will behave

Question 1

What is the electromagnetic spectrum?

Answer 1

The electromagnetic spectrum is a family of (transverse) waves that all travel at the same speed in a vacuum, 300,000,000m/s

Question 2

What are gamma rays?

Answer 2

Gamma rays have very high energy and can ionise (kill and damage) cancer cells, but they are also used to image the body

Question 3

What are x-rays?

Answer 3

X-rays are also ionising, and are also used in medical imaging

Question 4

What are ultraviolet?

Answer 4

Ultraviolet light can ionise skin cells causing sun-burn

Question 5

What is infrared?

Answer 5

Infrared radiation is used for heating and communications, such as in remote controls and optic fibres

Question 6

What are microwaves?

Answer 6

Microwaves are also used for heating and communicating, particularly as mobile phone signals. There are some public concerns about possible health risks associated with the microwaves used to transmit mobile phone signals, and in particular, the long term exposure to low levels of microwaves of children

Question 7

What are radio waves?

Answer 7

Radio waves are used for communication over much longer distances, transmitting TV and radio programmes

Question 8

Do all parts of the electromagnetic spectrum carry out information and energy?

Answer 8

All parts of the electromagnetic spectrum can carry information and energy. Stars also emit all parts of the spectrum giving us information about their composition and behaviour

Question 9

What’s thermal radiation?

Answer 9

All objects emit electromagnetic radiation. Very cold objects are emitting very little radiation.

But as the temperature of the object increases so does the amount of radiation emitted and the frequency of the emitted waves as well.

We recognise this emitted radiation as heat energy when the emitted waves become infrared, but extremely hot objects like stars are emitting all parts of the spectrum in different amounts depending on the stars temperature, mass, composition and stage in its life cycle. The characteristic emission spectrum of a hot object is often called is ‘blackbody’ radiation curve.