P12 Electromagnetic Waves

Question 1

How are EM waves made?

Answer 1

Oscillating electric and magnetic field

Question 2

How are alternate currents made?

What do they produce?

Answer 2

Made up of oscillating charges which produce osillating electric and magnetic fields aka electrmagjetic waves

Question 3

What does the frequecncy of a wave equal to?

Answer 3

The alternating current.

Question 4

How do you produce radio waves?

Answer 4

Ossilations in an electrical circut.

Question 5

What are radio waves used for?

Answer 5

Communication

Question 6

How long is the wavelength of a radio wave?

Answer 6

1-10km

Question 7

What is diffraction?

What waves diffract?

Answer 7

The prosses of which a wave bends around an object eg a hill. Therefore radio waves can be recived even when you cannot conect the transmitter and reciever with a straight unbrocken line.

Waves with longer wavelengths difracts better.

Question 8

How does the wavelength of a wave affect it’s ability to go through the ionesphere

Answer 8

The longer the wavelength the more chance it has of passing through the ionesphere. Waves with a wavlength of about 1km-10km can pass through it but waves with a wavelength of about 10m-100m can’t and will reflect off of it.

Question 9

What waves are used for TV and FR radios?

Answer 9

Radio waves. They use shorter wavelengths so they do not refract well.

Question 10

What is the order of the EM Spectrum

Answer 10

Radio Waves
Micro Waves
Infrared Radiation
Visable Light (In order of Red Orange Yellow Green Blue Indigo Violet)
UltraViolet
X-rays 
Gama-Rays

Question 11

Which wave has the shortest wavelength?

Answer 11

Gamma-Rays

Question 12

Which wave has the longest wavelength?

Answer 12

Radio-Waves

Question 13

Which waves have the highest frequency?

Answer 13

Gamma-Rays

Question 14

What wave has the lowest frequency

Answer 14

Radio Waves

Question 15

Give 2 uses for Radio waves

Answer 15

Radio signals
Tv signals
Walky talkys

Question 16

Give 2 uses of Micro Waves

Answer 16

Cooking food
Radar
MOBILE phone

Question 17

Give 2 uses of infrared radiation

Answer 17

Thermal imaging camaras
Night vision
Cooking (not with a microwave)

Question 18

Give 2 uses of Visable light

Answer 18

Sight

Cammara

Question 19

Give 2 uses of UltraViolet

Answer 19

Detective forgery money

To clean water

Question 20

Give 2 uses of X-rays

Answer 20

Medical diagnosis

Security

Question 21

Give 2 uses of Gamma-rays

Answer 21

Medical diagnosis
Sterilise medical equipment
Kill cancerous cells

Question 22

Give 2 dangers of Radio waves

Answer 22

There are none

Question 23

Give 2 dangers of Microwaves

Answer 23

Internal heating

Question 24

Give 2 dangers of InfraRed Radiation

Answer 24

Internal heating leading to burns

Eye damage

Question 25

Give 2 dangers of visable light

Answer 25

Eye damage

Question 26

Give 2 dangers of UltraViolet

Answer 26

Sun burn | Skin cancer

Question 27

Give 2 dangers of X-Rays

Answer 27

Radiation which leads to cancer | Damage of the skin

Question 28

Give 2 dangers of Gamma-Rays

Answer 28

Radiation leading to cancer Skin or blood diseases Kills cells

Question 29

What is an optical fibre?

Answer 29

Thin glass of plastic fibres that can carry data over long distances as pulses of visable light know as total internal reflexion They are very quick

Question 30

How fast do all electromagnetic waves travel in a vacume

Answer 30

3x10^8

Question 31

How do you calcuate wave speed?

Answer 31

Ws = F X Wl Wave Speed (m/s) = Frequency (Hz) X Wave Length (M)

Question 32

What are 3 things all EM waves have in common?

Answer 32

They travel at 3X10^8 m/s in a vacume They can all travel through a vacume They are all transverce waves

Question 33

What are carrier waves used for?

Answer 33

TV signals and satalite communication

Question 34

1Sv = ?mSv

Answer 34

1000mSv