Did You Get The Message? Flashcards Preview

Baldragon Academy S3 Physics > Did You Get The Message? > Flashcards

Flashcards in Did You Get The Message? Deck (68):
1

What is meant by the amplitude of a wave?

It is the distance from the centre of the wave to the crest or trough.

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2

Describe how to measure the speed of sound with two students using a clapper board, stop watch and trundle wheel.

  • One student takes the clapperboard and stands still.
  • The other students takes the stop watch and uses the trundle wheel to measure a set distance away.
  • The first student shuts the clapper board.
  • The other student starts the stop watch when they see the clapper shut and stops it when they hear the sound.
  • Speed of sound is calculated by distance between the students divided by the time on stop watch.

3

What is the energy change in a microphone?

Sound to electrical energy

4

You are 10km from a thunder storm. You count 15 seconds between seeing the lightning and hearing the thunder. You repeat this after the next lightning strike, the time between the lightning and the thunder is now 10 seconds. What does this tell you?

The storm has moved closer to you.

5

What is the purpose of the tuner in a radio?

To select one frequency

6

On an oscilloscope screen what would a loud sound look like?

Wave with a large amplitude - tall wave

7

What is the purpose of the amplifier in a radio?

To make the weak signal stronger

8

What is the unit for frequency?

Hertz (Hz)

9

Give an advantage of mobile phones

  • No wires - can be used anywhere
  • Acts as many devices
  • Can always be in contact with people
  • Fast to use in an emergency

10

What is the purpose of the aerial in a radio?

To detect all radio frequencies

11

Give an advantage of using a Landline phone system

  • Easy to understand message
  • Fast
  • Sends speech rather than a code

12

What is the unit for wavelength?

Metres (m)

13

What do waves transfer?

Energy

14

What is the difference in the two waves shown below?

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The top wave has a bigger amplitude and so has more energy.

(Or the bottom wave has a smaller amplitude so has less energy)

15

What is the purpose of the decoder in a radio?

Picks out the useful audio part of the signal

16

Describe how to measure the speed of sound using the equipment below.

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  • Make a loud sound to the left of the first microphone.
  • When the sound reaches microphone one it starts the fast timer, when the sound reaches the second microphone this stops the timer.
  • Measure the distance between the microphones using a metre stick.
  • The speed is calculated from distance between the microphones divided by the time on fast timer.

17

What happens to the speed of light as it travels from air into glass?

The speed of light in glass is slower than the speed of light in air.

18

What is the unit for speed?

metres per second (ms-1)

19

Does a light ray always change direction when it undergoes refraction?

No.

20

Which device can be found in the mouthpiece of a landline phone?

Microphone

21

Which wave property is illustrated below?

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Wavelength

22

On an oscilloscope screen what would a high frequency sound look like?

Many waves on the screen

23

What speed does light travel at in an optical fibre?

2 x 108ms-1

24

What is the unit for time?

Seconds (s)

25

Explain how to send a signal using a Morse Code telegraph.

  • When the switch is closed the circuit is completed.
  • Hold the switch down for a long time to get a dash, a short time for a dot
  • Use an agreed code

26

What happens to a light ray as it travels from water into air?

It speeds up and changes direction away from the normal.

27

What speed do the electrical signals travel in a metal wire system?

Almost 3 x 108ms-1

28

Give a disadvantage of a Morse Code Telegraph for sending signals.

  • Easy to tap into
  • Easy to disrupt
  • Easy to misunderstand the mesage being sent
  • Need the system to be manned at all times to receive the signals

29

In the diagram below, where is;

  • the normal ?
  • the angle of incidence?
  • the angle or refraction?

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See diagram

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30

What is an echo?

A reflection of sound

31

What path will the ray of light take as it passes through the glass prism?

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Light ray is refracted at air/glass boundary and glass/ air boundary. Both result in a change of direction.

As it enters the block the speed of the light decreases and it changes direction towards the normal.

As it leaves the block the speed of the light increases and it changes direction away from the normal.

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32

What is meant by the frequency of a wave?

The number of waves per second.

33

Give a disadvantage of optical fibres

  • Difficult to join

34

What does d stand for?

distance

35

What does v stand for?

Speed

36

What is the energy change in a loudspeaker?

Electrical to sound energy

37

Give an advantage of a Morse Code Telegraph for sending signals.

  • It is fast
  • Simple / Easy to set up

38

You are 10km from a thunder storm. You count 15 seconds between seeing the lightning and hearing the thunder. How do you calculate how far away the storm is?

Use d = vt

Where v is the speed of sound.

t is 15 seconds.

39

What is the speed of a radio wave in air?

3 x 108ms-1

40

How does light travel through an optical fibre?

It travels by Total Internal Reflection

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41

What path will the ray of light take as it passes through the glass prism?

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Light ray still experiences a change of speed - it is still refracted but no directional change.

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42

What is the purpose of the loudspeaker in a radio?

To convert electrical energy into sound energy

43

What is meant by the critical angle?

The angle of incidence that gives an angle of refraction of ninety degrees.

Red lines on diagram illustrate this.

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44

What does f stand for?

Frequency

45

On an oscilloscope screen what would a low frequency sound look like?

Few waves on the screen.

46

On an oscilloscope screen what would a quiet sound look like?

Small amplitude - small height wave

47

What effect is shown here?

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Diffraction

48

What is the speed of microwaves in air?

3 x 108ms-1

49

Which device can be found in the earpiece of a phone?

Loudspeaker

50

Give a disadvantage of a landline phone system

  • Metal wires can be easily tapped
  • Need people at both ends to receive and send signals

51

What is the difference in the two waves shown below?

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The bottom wave has a higher frequency. (Or the top wave has a lower frequency)

52

You are 5km away from a thunder storm. What reaches you first - the thunder or the lighning? Explain your answer.

The lightning. The speed of light is faster than the speed of sound.

53

State one advantages of using radio to send signals.

  • Can broadcast to many people at the same time
  • Broadcasts speech so it will not be misunderstood

54

Give an advanage of optical fibres over metal wire systems

  • Carry more data at once
  • Cheaper
  • Do not corrode / rust
  • Carry a jigher quality signal

55

What does t stand for?

Time

56

What is the speed of a light signal in glass?

2 x 108ms-1

57

What type of signal do mobile phones use?

Microwaves

58

What is the unit for distance?

metres

59

What happens to a light ray as it travels from air into glass?

It will slow down and change direction towards the normal.

60

What is meant by the wavelength of a wave?

It is the distance from a point on one wave to the same point on the next.

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61

Which wave property is illustrated in the diagram below?

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The amplitude of a wave.

62

What are the 5 parts of a radio?

  • Aerial
  • Tuner
  • Decoder
  • Amplifier 
  • Loudspeaker

63

State a disadvantage of radio to send signals

  • Not private - everyone receives the signal
  • Cannot always get a signal

64

What is meant by refraction?

Refraction is the change of speed of light as it enters a different medium - often observed as a change in direction.

65

What does λ stand for?

Wavelength

66

What happens if light is shone onto a surface at an angle greater than the critical angle?

It is no longer refracted it is totally internally reflected.

67

What is the normal?

An imaginary line at 90 degrees to the surface. All angles are measured from here.

68

Give a disadvantage of a mobile phone

  • May not always get a signal
  • Can run out of charge
  • Can be expensive