Electromagnetic Spectrum

Question 1

General Rules that applied to EM waves

Answer 1

1. High-frequency electromagnetic waves are more energetic and more able to penetrate media than low-frequency waves.
2. High frequency electromagnetic waves can carry more information per unit time than low-frequency waves.
3. The shorter the wavelength of any electromagnetic wave probing a material, the smaller the detail it is possible to resolve.

Question 2

Properties of EM waves

Answer 2

1. They are transverse wave.
2. They can travel in a vacuum as they do not require a medium to travel.
3. They travel at the same speed (3.o x 10^8 m/s) in vacuum.
4. They transfer energy from one place to another.
5. They all obey the wave equation.
6. When an electromagnetic wave travels from one medium to another, its speed and wavelength changes while frequency do not change.
7. They obey laws of reflection and refraction.
8. They do not carry any electric charges.
9. They are produced when a charge is accelerated.

Question 3

Visible spectrum of light

Answer 3

(Longest wavelength/shortest frequency) Red, Orange, Yellow, Green, Blue, Indigo, Violet

Question 4

Radiowaves

Answer 4

Longest wavelengths (10^-1 to 10^4m)
Radio communication, television transmission, radar system, navigation systems, telecommunication

Question 5

Microwaves

Answer 5

wavelength: 10^-3 to 10 ^-1 m
Satellite transmission
Microwave ovens

Question 6

Infra-red Radiation

Answer 6

wavelength: 10^-7 to 10^-3 m
Remote control devices, intruder alarms, ear thermometer

Question 7

Visible light

Answer 7

wavelength: 4 x 10^-7 to 7 x 10^-7 m
optical fibre, photosynthesis

Question 8

Ultraviolet

Answer 8

Wavelength: 10^-8 to 10^-7 m
Sunbed, sterilisation of medical equipment, forgery detection

Question 9

X-rays

Answer 9

Wavelength: 10^-10 to 10^-8m
Security check at airport, radiology, radiography

Question 10

Gamma Rays

Answer 10

Wavelength: <10^-11 m
Radiation therapy, Gamma knife radiosurgery

Causes ionisation in cells