Waves Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the definition of amplitude?

A

The maximum displacement from the zero point.

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

Define wavelength.

A

The distance between two points with the same phase.

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

What is the definition of period?

A

The time for one complete cycle.

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

Define frequency.

A

The number of complete oscillations per second.

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

Give frequency in terms of C and wavelength.

A

Frequency = C/Wavelength.

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

Define a Transverse wave.

A

A wave in which, the oscillations are perpendicular to the direction of movement of the energy/information.

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

Define a Longitudinal wave.

A

A wave in which, the oscillations are parallel to the direction of movement of the energy/information.

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

Define a wave.

A

A way to move energy or information from one point to another, in a medium, without the medium moving between those points.

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

What is the law of superposition?

A

When two similar waves meet at the same point, the resulting displacement is the vector sum of the individual displacements.

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

What is more energetic, red light or blue light?

A

Blue light > ultraviolet > Xrays > Gamma rays

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

Do radio waves have a high or low frequency/wavelength?

A

Radio, micro and infra red have a high wavelength and a low frequency.

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

Do Gama rays have a high or low frequency/wavelength?

A

Gama, X ray and ultra violet have a low wavelength and a high frequency.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the audible spectrum limits?

A

below 20Hz is subsonic and above 20,000Hz is UltraSonic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Define Reflection.

A

When a wave bounces off the boundary between one material and another.

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

What is the Law of reflection?

A

I = r

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

What is the Law of refraction?

A

(n1)Sin(O1) = (n2)Sin(O2)

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

How do we find “n”

A

n = speed of light in vacuum/speed of light in material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Does light take the path of shortest time or distance?

A

Light takes the path of shortest time.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

When does total internal reflection occur?

A

when the angle of incidence is bigger than the critical angle.

20
Q

How do we find the critical angle?

A

(n1)Sin(critical angle) = 1

21
Q

Two waves intersect with a phase difference of 0*, what interference occurs?

A

Constructive interference.

22
Q

Two waves intersect with a phase difference of 180*, what interference occurs?

A

Destructive interference.

23
Q

When do beats occur?

A

Two Waves

Same Direction

Slightly different phase

24
Q

What is phase?

A

Phase is the difference in position of one wave to another- ie how far one peak is from another on a different wave.

25
Q

What is the fundamental frequency of a Node Node or antinode antinode standing wave? (an open pipe)

A

f = V/2L

26
Q

What is the nth harmonic of a Node Node or antinode antinode standing wave? (an open pipe)

A

f = nV/2L

27
Q

What is the fundamental frequency of a Node Antinode standing wave? (a closed pipe)

A

f = V/4L

28
Q

What is the (2n-1)th harmonic of a Node Antinode standing wave? (a closed pipe)

A

f = (2n-1)V/4L

29
Q

When is the point of maximum diffraction?

A

When the wavelength = gap size

30
Q

What is the equation for “just resolving”

A

wavelength/hole width = width of two objects/distance the two objects are away from the hole

31
Q

what does double slit detraction look like?

A

a wide single slit diffraction envelope with interference peaks within it.

32
Q

What is the equation for multislit defraction?

A

(nth Maxima)(wavelength of light) = (distance between slits)(sin(angle of nth Maxima))

33
Q

What is the equation for multi slit diffraction?

A

(peak number)(wavelength) = (distance slits are apart) sin(theta)

34
Q

what is the difference in meaning for “n” in the single and multi slot diffraction equations?

A

single slit - n = trough number

multislit - n = peak number

35
Q

define coherence

A

two waves are coherent if the phase difference between them is constant

36
Q

what does Young’s slit experiment show us?

A

it shows us the wave nature of light

37
Q

how does slit width effect multislit diffraction pattern?

A

as the slit width increases, the angle of the first trough of the envelope decreases.

38
Q

when using a diffraction grating, how do you find the distance between the slits?

A

distance between slits = 1/ slits per mm

39
Q

what happens as we add the number of slits in multislit diffraction?

A

the peaks all get sharper

40
Q

what is a missing Maxima in regards to multislit diffraction?

A

whan a peak of the multislit diffraction pattern lays perfectly on a trough of the single slit envelope

41
Q

how does a monochromater work and what does it do?

A

it gives you a single wavelength of light from many

it works by using a diffraction grating to split the whitelight into its individual wavelengths, then, using a screen with a small hole in it, it can select the wavelength it would like.

42
Q

how can we measure wavelength?

A

using a spectrometer. A spectrometer takes in a combination of light wavelengths, spits them using a diffraction grating, and then uses a “telescope” to rotate until light is seen- in which case the user can note the angle the light has been split to.

this can then be used to find the wavelength using the equation (peak number)(wavelength) = (slit distance)sin(measured theta)

43
Q

what does polarisation mean?

A

an electromagnetic wave in which only one orientation of the electromagnetic wave exists.

44
Q

how can we create polarised light?

A

AT SOURCE

em waves can be produced by elections accelerating
if we confine these electrons to one axis of movement we can produce polarised light
example: electrons moving across stretched polymer fibres

FROM UNPOLARISED LIGHT

Polaroid blocks all light passing through it apart from in one direction- think of a letterbox
by passing unpolarised light through Polaroid, it will come out at a lower intensity, but polarised
in this situation:
(intensity out) = (intensity if theta = zero)cos squared (theta)

45
Q

what is the equation for mallus’ law?

A

(intensity out) = (intensity at theta = zero)cos squared (theta)

46
Q

in words, what is Brewster’s angle?

A

when light hits a material such as glass, it will diffraction. This diffraction will cause a reflection to occur also. if the angle between the reflected and refracted rays are 90 degrees, it means that the reflected rays direction of energy transfer is parallel with the direction of travel in one plane. This means the reflected light is polarised. the Lange if incidence for which this occurs is the Brewster’s angle.