Waves

Question 1

What is wavelength?

Answer 1

The length of a full cycle of a wave

Question 2

What is amplitude?

Answer 2

The space from the middle line to the trough or crest

Question 3

What is frequency?

Answer 3

The number of complete waves passing a certain point per second

Question 4

What are the two types of wave?

Answer 4

Transverse and longitudinal

Question 5

What are transverse waves?

Answer 5

Waves that have sideways vibrations e.g. electromagnetic waves, ripples on water
l l l
l l l l l
l l l etc

Question 6

What direction are the waves in transverse waves?

Answer 6

Perpendicular (at 90 degrees) to the direction of energy transfer of the wave

Question 7

What are longitudinal waves?

Answer 7

Waves that have vibrations along the same line e.g. sound waves, shock waves
l l l l lll l l l l l l lll l l l l l l l llll l l l l l l llll l l l l etc

Question 8

What direction are the waves in longitudinal waves?

Answer 8

Parallel to the direction of energy transfer of the wave

Question 9

What are the units in the speed=frequency x wavelength?

Answer 9

m/s, Hz, m

Question 10

How can waves be affected?

Answer 10

By reflection, refraction and diffraction

Question 11

What is reflection?

Answer 11

When light bounces off an object and allows us to see it

Question 12

What allows you to see your reflection in a mirror and not a piece of paper?

Answer 12

The paper has a very uneven surface so the light reflects off at different angles. However, the mirror is very smooth and shiny, so the light just reflects straight off, allowing you to see your reflection

Question 13

What is the law of reflection?

Answer 13

Angle of incidence = angle of reflection

Question 14

How do you draw a ray diagram for an image in a plane mirror?

Answer 14

1. Draw the virtual image behind the mirror the same size and the same distance from the mirror
2. Then draw a ray from the top of the eye to the top of the virtual image (bold in front , dotted behind the mirror)
3. Draw the incident ray from where the line touches the mirror to the top of the real object
4. Do the same for the bottom ray

Question 15

What is refraction?

Answer 15

When waves change direction as they go through an object due to them changing speed through different densities

Question 16

What happens when a wave refracts?

Answer 16

It hits an object and slows down, and if it hits it straight on at the normal, it won’t bend, but if it hits it at an angle, it will bend towards the normal, the bend away from the normal when it comes out

Question 17

What is diffraction?

Answer 17

When waves pass through a gap and spread out

Question 18

How does the size of the gap affect diffraction?

Answer 18

When the gap equals the wavelength, there is the maximum diffraction, if the gap is much wider, there is very little diffraction, and if the gap is only a little bit wider, it will slightly diffract

Question 19

What is the electromagnetic spectrum?

Answer 19

A continuous spectrum of electromagnetic waves

Question 20

What are the waves in the EM spectrum?

Answer 20

Radio Microwaves Infrared Visable Ultra-violet X-rays Gamma

Question 21

What are the wavelengths in the EM spectrum?

Answer 21

From about 10(-15)m to 10(4)m

Question 22

What speed do EM waves travel at?

Answer 22

The speed of light (3 x 10(8) m/s)

Question 23

What are radiowaves used for?

Answer 23

Communication, because the shorter waves reflect off the ionosphere and the longer waves diffract around the earth

Question 24

What are microwaves used for?

Answer 24

Satellite communication and mobile phones, as they can pass through the ionosphere to reach satellites, which transmit the signal back to earth, and for heating food as they are the right wavelength to pass through water molecules and heat them up

Question 25

What is infrared used for?

Answer 25

Remote controls and optical fibres as they can carry data over long distances by emitting different patterns of infrared to send different commands

Question 26

What is visible light used for?

Answer 26

Apart from seeing, visible light is used for photography, as the lens focuses visible light onto a sensor which creates a picture

Question 27

How do we hear sound?

Answer 27

The waves travel to our ear and eventually reach the eardrum

Question 28

Why can’t sound travel in space but light can?

Answer 28

Because sound needs particles to travel but light doesn’t

Question 29

Why can you hear around a corner but not see?

Answer 29

Because light waves can only be reflected, so they can’t go around corners, but sound rays can be reflected and diffracted, so they can diffract around corners

Question 30

What is a high frequency?

Answer 30

A high pitch with short wavelengths

Question 31

What is a high amplitude?

Answer 31

A loud sound