Waves Flashcards

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1
Q

How are stationary waves formed?

A

They are formed when 2 progressive waves with the same amplitude , frequency and phase difference travelling in opposite directions interfere with each other

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2
Q

How long is a wavelength in Pi

A

2Pi

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3
Q
Equation for fringe separation 
W=fringe separation 
D=distance from slits to screen 
s=slit spacing
wavelength 
arrange for slit spacing to be the subject
A

s=(wavelength x D)/w

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4
Q

How are bright fringes formed

A

Light from one slit reinforces light from other slit

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5
Q

How are dark fringes formed

A

Light from one slit cancels light from other (light waves are 180 degrees out of phase

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6
Q

Equation for wavelength with c,f,λ

A

c/f=λ

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7
Q

The equation for fringe spacing

A

λD/S=W

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8
Q

What is a node?

A

This is points of no displacement where the nodes remain in the same position. Particles at those points are not vibrating at all and they have no energy.

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9
Q

The equation for Diffraction Grating

A

d sin(θ)=nλ

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10
Q

The refractive index of air

A

1.000277 or 1

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11
Q

The equation for the refractive index of a substance

A

n=C/Cs

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12
Q

Total internal reflection: sinθc = ???

A

n2/n1 where n2>n1

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13
Q

The refractive index of Diamond

A

2.417

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14
Q

Snell’s law for refraction of a boundry

A

n1 sinθ1 =n2 sinθ2

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15
Q

What are coherent sources

A

The light emitted is in constant phase difference and same frequency

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16
Q

How do you reinforce a fringe

A

Have wavelength arrive in phase with monochromatic light

E.G. π,2π,3π

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17
Q

How do you cancel the path difference

A

May light 180 degrees out of phase

E.G. π/2, 2π/3, 3π/4

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18
Q

The refractive index of Diamond

A

2.417

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19
Q

A light ray is directed into a glass block that has a refractive index of 1.5 at an angle of incidence of 40°. Calculate the angle of refraction.

A

sin−1(sin40/1.5)

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20
Q

What is the diffraction grating equation
Wavelength
Diffraction grating=d

A

d x sin(theta)=n x wavelength

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21
Q

How to calculate number of slits per metre on the grating
d = diffraction grating
N = number of slits per metre

A

N=1/d

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22
Q

sin(i)/sin(r) = C/?

A

C/Cs

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23
Q

Does the frequency change when diffraction occurs?

A

no or nah m8

24
Q

Finish the sentence

The smaller the value of the diffraction grating the greater the ___________________________

A

Angle of diffraction

25
Q

What are the three types of spectra

A

Continuous
Line emission
Line absorption

26
Q

What kind of light is produced by a laser

A

Monochromatic

27
Q

What are electromagnetic waves

A

Oscillating electric and magnetic fields that go through space without the need of a substance

28
Q

Which waves are considered electromagnetic waves

A
Radio waves
Microwaves
Infrared radiation 
Light
Ultra violet 
X-rays 
and gamma radiation
29
Q

Do longitudinal waves move parallel or vertical and do they compress or not

A

Parallel

Do compress

30
Q

What waves are classed as longitudinal

A

Sound waves

Primary seismic waves

31
Q

Do transverse waves move parallel or perpendicular

A

They are perpendicular

32
Q

WHAT IS TOTAL INTERNAL REFLECTION?

A

WHEN A LIGHT RAY REFLECTS OFF THE INSIDE OF A TRANSPARENT MATERIAL.

33
Q

when can total internal reflection take place?

A
  1. When the angle of incidence exceeds the critical angle of the material.
  2. The incidence material has a larger refractive index then the other material.
34
Q

why is a laser used to produce light

A

so that the light produced is of the same frequency

35
Q

give a use of internal reflection

A

optical fibers

36
Q

what is the layer called that covers optical fibres?

A

Cladding

37
Q

What is an antinode?

A

These are points on the waveform where the particles are of a displacement and energy.

38
Q

Describe what fringe pattern you would see when white light is the source of light?

A

You would see the colours of the spectrum and the centre is white as every colour contributes to the central pattern.the inner fringes are blue and outer are red as the red fringes are spaced out further than the blue fringes.

39
Q

What is the wavelength for the first harmonic if the distance of the string is 0.30m?

A

It is 0.60m because the first harmonic is half of the wavelength. (Use equation λ1=2L)

40
Q

What is the wavelength for the second harmonic if the distance of the string is 0.60m?

A

It is 0.60m because the second harmonics wavelength is equal to the distance of the wire. (Use equation λ2=L)

41
Q

What is the wavelength for the second harmonic if the distance of the string is 3m?

A

It is 2m because the third harmonic is two thirds of the distance of the string.(use equation λ3=2/3L

42
Q

What happens to the wavelength as you increase frequency of a stationary wave?

A

The wavelength also increases.

43
Q

What is a coherent source?

A

It is a source with a constant phase difference and the same frequency.

44
Q

what is slit separation?

A

It is the distance between the end of i slit and the end of the other or middle to middle or begging to begging.

45
Q

When dark fringes are formed what type of interference is this?

A

Destructive interference.

46
Q

What safety precaution is needed when using a laser?

A

Never look directly into the light.

47
Q

Which waves are transverse

A

Electromagnetic
Secondary seismic
Waves on string or wire

48
Q

How do you know if a transverse wave is plane polarised

A

When vibrations stay in one plane only

49
Q

How do you know when a wave is unpolarised

A

When the wave moves to a different plane

50
Q

dark fringes are made when light , with a phase difference of Pi apart, meats each other. is this true or false?

A

true

51
Q

What is an example of making a polarised wave

A

Having a wave on a string go through a slit In a board

52
Q

Use of polarising light in real life

A

Sunglasses

53
Q

What happens if polarised light passes through a Polaroid at 90 degrees to the polarised light

A

It won’t go through

54
Q

What is the definition of displacement of vibrating particles

A

It’s distance and direction from equilibrium position

55
Q

What is the amplitude of a wave

A

Maximum displacement of a vibrating particle

56
Q

What is the wavelength

A

Least distance between two adjacent vibrating particles with the same displacement and velocity