Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics > Waves > Flashcards

Waves Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

What is a progressive wave?

A

A moving wave that transfers energy from one place to another without transferring any material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does it mean if a wave is reflected?

A

Bounce back when they hit a boundary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does it mean when a wave refracts?

A

The wave changes direction and speed as it enters a new median

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

When does it mean when a wave is diffracted?

A

Wave spreads out as it passes through a gap or round an object.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is displacement?

A

How far a point on the wave has moved from its undisturbed position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is amplitude?

A

The maximum displacement from a wave’s undisturbed position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is wavelength?

A

The length of one whole wave oscillation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the period?

A

Time taken for one whole wave cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is frequency?

A

Number of whole wave cycles passing a given point per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is phase?

A

A measurement of the position of a certain point along the wave cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is phase difference?

A

The amount by which one wave lags behind another wave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do to measure the speed of sound in air?

A
  • Set up 2 microphones a set distance apart connected to the same computer with different inputs so that the signals from each microphone can be picked up.
  • Use a signal generator to produce a sound from a loudspeaker and use the computer to record the time between the first and second microphone picking up the sound.
  • Then measure the time delay between the first peak of the signal received by each microphone on a graph of voltage against time.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do to measure the speed of sound in water?

A
  • Use a ripple tank and measure the depth of the water using a ruler.
  • Then turn on the ripple tank dipper and increase the frequency until the wave appears to not be moving ( a stationary wave is formed).
  • Then use a ruler on a white piece of paper below to measure the wavelength between 2 peaks.
  • Then repeat for different depths of the ripple tank.
  • Use wave speed equation to calculate speed of sound in water.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a transverse wave?

A

Wave oscillations move perpendicular to the direction of energy propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a longitudinal wave?

A

Wave oscillations move parallel to the direction of energy propagation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a polarised wave?

A

A wave that only oscillates in one plane.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the principle of superposition?

A

When two or more waves pass through each other, the resultant displacement is equal to the vector sum of all the individual displacements

18
Q

What is a stationary wave?

A

The superposition of two progressive waves of equal frequency and amplitude but opposite direction.

19
Q

What is a node?

A

Where the amplitude of a wave equals 0

20
Q

What is an anti-node?

A

Points of maximum amplitude

21
Q

What is diffraction?

A

The spreading of waves as they pass through a gap of similar size to their wavelength.

22
Q

What does monochromatic mean?

A

One colour, single frequency

23
Q

What does coherent mean?

A

Fixed phase difference and same frequency and wavelength.

24
Q

What causes bright fringes on a diffraction pattern?

A

It is due to total constructive interference as waves arrive at a screen in phase

25
Q

What causes dark fringes on a diffraction pattern?

A

It is due to total destructive interference as waves arrive at a screen completely out of phase

26
Q

How can you increase the width of the central maxima on a diffraction pattern?

A
  • Increase the wavelength of the light
  • Decrease the slit width
27
Q

What is Two source interference?

A

Where waves from 2 sources (superimposing) to form a constructive and destructive interference pattern.

28
Q

What is path difference?

A

It is a measure of how far ahead a wave is compared to another.

29
Q

What is a diffraction grating?

A

A slide containing many equally spaced slits very close together.

30
Q

What can Diffraction gratings be used for?

A
  • Line absorption spectra
  • X-ray crystallography
31
Q

What is Line absorption spectra?

A

When you split up light from a star, the line absorption spectra shows you which elements are present in the star.

32
Q

What is X-ray crystallography?

A

When X-rays are directed at a thin crystal sheet, a diffraction pattern is shown. The pattern can be used to measure the atomic spacing of molecules.

33
Q

What is the refractive index?

A

It is a property of a material which measures how much it slows down light passing through it.

34
Q

What is the critical angle?

A

Where the angle of refraction is equal to 90°

35
Q

What is total internal reflection?

A

Complete reflection if a ray of light in a medium.

36
Q

What is an application of TIR?

A

Optical fibres carrying information in the form of pulses of light.
- Internet data
- Light can carry more information due to its high frequency
- Light doesn’t heat up the fibre, therefore there is very little energy dissipation
- Minimal signal loss

37
Q

What are the 2 types of signal degradation?

A
  • Absorption: part of the signals energy is absorbed by the fibre reducing the amplitude of the signal
  • Dispersion: this caused pulse broadening. Broadened signals can overlap causing a loss of information.
38
Q

What are the 2 types of Dispersion and what can be used in order to reduce this?

A
  • Modal Dispersion: Because rays of light enter the fibre at different angles, some TIR more than others, leading to shorter and flatter paths.
    Solution: make core narrower
  • Material Dispersion: light of different frequencies travel at different speeds along the fibre, therefore taking different amounts of time to arrive.
    Solution: use monochromatic light

An optical fibre repeater reduces both absorption and dispersion by regenerating the signal during its travel.

39
Q

What is the description of the pattern produced when monochromatic light passes through a very narrow slit?

A

A wide central maximum with narrower side fringes.

40
Q

A diffraction pattern is formed by passing monochromatic light through a single slit. If the width of the single slit is decreased, what happens to the width and intensity of the central maximum?

A

Intensity will decrease
Width will increase.

41
Q
A

Physics (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions