EM Waves

Question 1

What are the 7 types of waves

Answer 1

Radio
Micro
Infra red
Visible light
Ultra violet 
X-ray
Gamma ray

Question 2

What is the longest wavelength

Answer 2

Radio waves

Question 3

What is the shortest wavelength

Answer 3

Gamma rays

Question 4

What is the same about all the EM waves travelling in a vacuum

Answer 4

They travel in the same direction

Question 5

EM waves with higher frequencies have…

Answer 5

Shorter wavelengths

Question 6

Why do EM waves have different purposes

Answer 6

They have different properties

Question 7

What is the main use of radio waves

Answer 7

Communication

Question 8

What is the general size of radio waves

Answer 8

Longer than 10cm

Question 9

Why is it possible for long-wave radio to be transmitted from London to hallway around the world

Answer 9

Long wavelengths diffract around the curved surfaces of the earth

Question 10

What does the diffraction effect enable

Answer 10

Radio signals to be received regardless of whether the receiver is in line with the transmitter

Question 11

Why can short wave radio signals be received at long distances

Answer 11

They reflect of the ionosphere

Question 12

What is the ionosphere

Answer 12

An electrically charged layer in the earth’s upper atmosphere

Question 13

Where are medium-wave signals reflected from

Answer 13

The ionosphere

Question 14

What does reflection of medium-wave signals depend on

Answer 14

The atmospheric conditions and the time of day

Question 15

What are microwaves used for

Answer 15

Satellite communication

Mobile phones

Question 16

Why are microwaves used for satellite communication instead of radio waves

Answer 16

They can pass through the earth’s watery layer whereas microwaves can’t

Question 17

Where do mobile phone micro-waves travel between

Answer 17

Phone and the transmitter

Question 18

Why do some people think living near a mast or excessive use of your mobile phone is dangerous

Answer 18

Some wavelengths of microwaves are absorbed by water molecules and heat them up. If this water happens to be if your cells you might start to cook

Question 19

Is their any conclusive evidence for why people think using a mobile phone may be damaging to your health

Answer 19

No

Question 20

how do remote-sensing satellites use microwaves

Answer 20

To see through the clouds
Monitor oil spills
Track iceberg movement
See how much of a rainforest has been deforested

Question 21

What are infrared waves used for

Answer 21

Remote controls

Optical fibers

Question 22

What is the main remote control that uses infrared waves

Answer 22

Wireless remote controls

Question 23

How do remote controls work

Answer 23

Emit different patters of infrared waves to send different commands to the appliance

Question 24

What do optical fibers do

Answer 24

Carry data over long distances quickly

Question 25

What other waves - apart from infra red - do optical fibers and remote controls use

Answer 25

Visible light

Question 26

how do infrared waves work

Answer 26

The signal is carried as pulses or infra red radiation and is reflected off the sides of a very narrow core from one end of the fiber to the other

Question 27

What is visible light useful for

Answer 27

Photography

Question 28

What do cameras use to focus on visible light

Answer 28

The lens

Question 29

Where do cameras focus visible light onto using a lens

Answer 29

A light - sensitive film or electronic sensor

Question 30

What does the lens aperture do

Answer 30

Controls how much light enters the camera

Question 31

What does the shutter speed of a camera determine

Answer 31

How long the film or sensor is exposed to light

Question 32

What can a photographer do by varying the lens aperture and shutter speed of a camera

Answer 32

Capture as much or as little light as they want in their photograph