P1.5 The use of waves for communication and to provide evidence that the universe is expanding

Question 1

What do waves transfer?

Answer 1

Energy

Question 2

What is the amplitude?

Answer 2

The displacement from the rest position to the crest

Question 3

What is the wavelength?

Answer 3

The length of a full cycle of the wave, crest to crest

Question 4

What is the frequency?

Answer 4

The number of complete waves passing a certain point per second. Measure in hertz

Question 5

What are the two types of waves?

Answer 5

Transverse and longitudinal

Question 6

At what angle are the vibrations in transverse waves to the direction of energy transfer of the wave?

Answer 6

Perpendicular, at 90 degrees

Question 7

What are some examples of transverse waves?

Answer 7

Light and all other electromagnetic waves, waves on strings, ripples on water, slinky spring wiggled up and down

Question 8

In what position are vibrations in longitudinal waves to the direction of energy transfer of the wave?

Answer 8

Parallel

Question 9

What are some examples of longitudinal waves?

Answer 9

Sound waves, ultrasound, shock waves, slinky spring when you push the end

Question 10

What is the equation for wave speed?

Answer 10

Speed= Frequency x Wavelength

Question 11

How do all electromagnetic waves travel through a vacuum?

Answer 11

At the same speed

Question 12

What are the different areas of a longitudinal wave?

Answer 12

Rarefaction and compression

Question 13

What can all waves be?

Answer 13

Reflected, refracted and diffracted

Question 14

What is the law of reflection?

Answer 14

Angle of incidence = angle of reflection

Question 15

What is the name of the construction line perpendicular to the reflecting surface?

Answer 15

The normal

Question 16

What happens when light is travelling in the same direction and reflects from an even surface?

Answer 16

It is reflected at the same angle

Question 17

What is the image produced in a plane mirror?

Answer 17

The same size, upright, same distance, inverted, virtual

Question 18

What can radio waves, microwaves, infrared and visible light be used for?

Answer 18

Communication

Question 19

What happens to cause refraction?

Answer 19

Waves entering a more/less dense medium causing a change in direction

Question 20

What is diffraction?

Answer 20

When a wave gets spread out when passing through a gap or round an obstacle

Question 21

What is the electromagnetic spectrum?

Answer 21

Gamma ray, X-ray, Ultraviolet, Visible, Infrared, Microwave, Radio

Question 22

Which part of the spectrum has the the highest frequency?

Answer 22

Gamma

Question 23

Which part of the spectrum has the lowest frequency?

Answer 23

Radio

Question 24

Which part of the spectrum has the shortest wavelength?

Answer 24

Gamma

Question 25

Which part of the spectrum has the longest wavelength?

Answer 25

Radio

Question 26

Which is the only part of the spectrum we can see?

Answer 26

Visible light

Question 27

What are microwaves used for?

Answer 27

Satellite communication and mobile phones

Question 28

What is infrared used for?

Answer 28

Remote controls and optical fibres

Question 29

What is visible light used for?

Answer 29

Phtography

Question 30

How does sound travel?

Answer 30

As a longitudinal wave

Question 31

Where can't sound travel?

Answer 31

In a vacuum because there are no particles

Question 32

When are waves not refracted?

Answer 32

When travelling along the normal

Question 33

What are radio waves used for?

Answer 33

Television and radio

Question 34

What do sound waves cause?

Answer 34

Vibrations in a medium, picked up as sound

Question 35

What is the pitch of a sound determined by?

Answer 35

Its frequency

Question 36

What is the loudness of a sound determined by?

Answer 36

Its amplitude

Question 37

High frequency means...

Answer 37

Shorter wavelength

Question 38

What will sound waves do?

Answer 38

Reflect and Refract

Question 39

What are echoes?

Answer 39

Reflected sound waves

Question 40

Why is there a delay between the original sounds and the echo?

Answer 40

Because the echoed sound waves have to travel further

Question 41

When light waves enter a denser material they...

Answer 41

Slow down and bend towards the normal

Question 42

What happens when something emitting waves moves towards or away from you?

Answer 42

The wavelengths and frequencies seem different compared to when they are stationary. This is the Doppler effect

Question 43

The frequency of a source moving towards you will seem...

Answer 43

Higher and its wavelength will seem shorter

Question 44

The frequency of a source moving away from you will seem...

Answer 44

Lower and its wavelength will seem longer

Question 45

Which waves does the Doppler effect effect?

Answer 45

Longitudinal and Transverse

Question 46

What wave source could the Doppler effect involve?

Answer 46

Light, Sound or microwave

Question 47

What colour do distant galaxies appear to us?

Answer 47

Red

Question 48

What does the red-shift of other galaxies suggest to us?

Answer 48

The galaxies are moving away from us

Question 49

More distant galaxies have greater...

Answer 49

Red-shifts than nearer ones

Question 50

The galaxies moving away from us proves the universe is...

Answer 50

Expanding

Question 51

The further away the galaxies are, the faster they are moving and the...

Answer 51

Bigger the observed increase in wavelength

Question 52

What does the expansion of the universe suggest?

Answer 52

That the universe must have started at one point and started expanding

Question 53

What is the thought cause of this expansion of the universe?

Answer 53

The Big Bang

Question 54

What is cosmic background radiation?

Answer 54

A low frequency electromagnetic radiation coming from all parts of the universe, present shortly after the beginning of the universe

Question 55

What is the explanation of cosmic background radiation

Answer 55

After the Big Bang while the universe was very hot everything in the universe emitted very high frequency radiation. As the universe expanded and cooled the radiation dropped frequency

Question 56

If an object is moving away from us the light waves...

Answer 56

Get spread out which decreases the frequency and makes them appear red

Question 57

What colour would an object coming towards us appear to be?

Answer 57

Blue

Question 58

What is the only explanation for cosmic background radiation?

Answer 58

The big bang

Question 59

Is the Big Bang theory perfect?

Answer 59

No, there are still things that the big bang does not answer, e.g. the big bang predicts the universe's expansion slowing down but it actually appears to be speeding up

Question 60

Will the Big Bang theory ever be dropped?

Answer 60

It is more likely to be adapted to account for its weaknesses as many scientists are persuaded by it