Waves

Question 1

How are stationary waves formed?

Answer 1

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

Question 2

How long is a wavelength in Pi

Answer 2

2Pi

Question 3

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

Answer 3

s=(wavelength x D)/w

Question 4

How are bright fringes formed

Answer 4

Light from one slit reinforces light from other slit

Question 5

How are dark fringes formed

Answer 5

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

Question 6

Equation for wavelength with c,f,λ

Answer 6

c/f=λ

Question 7

The equation for fringe spacing

Answer 7

λD/S=W

Question 8

What is a node?

Answer 8

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.

Question 9

The equation for Diffraction Grating

Answer 9

d sin(θ)=nλ

Question 10

The refractive index of air

Answer 10

1.000277 or 1

Question 11

The equation for the refractive index of a substance

Answer 11

n=C/Cs

Question 12

Total internal reflection: sinθc = ???

Answer 12

n2/n1 where n2>n1

Question 13

The refractive index of Diamond

Answer 13

2.417

Question 14

Snell’s law for refraction of a boundry

Answer 14

n1 sinθ1 =n2 sinθ2

Question 15

What are coherent sources

Answer 15

The light emitted is in constant phase difference and same frequency

Question 16

How do you reinforce a fringe

Answer 16

Have wavelength arrive in phase with monochromatic light

E.G. π,2π,3π

Question 17

How do you cancel the path difference

Answer 17

May light 180 degrees out of phase

E.G. π/2, 2π/3, 3π/4

Question 18

The refractive index of Diamond

Answer 18

2.417

Question 19

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.

Answer 19

sin−1(sin40/1.5)

Question 20

What is the diffraction grating equation
Wavelength
Diffraction grating=d

Answer 20

d x sin(theta)=n x wavelength

Question 21

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

Answer 21

N=1/d

Question 22

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

Answer 22

C/Cs

Question 23

Does the frequency change when diffraction occurs?

Answer 23

no or nah m8

Question 24

Finish the sentence

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

Answer 24

Angle of diffraction

Question 25

What are the three types of spectra

Answer 25

Continuous Line emission Line absorption

Question 26

What kind of light is produced by a laser

Answer 26

Monochromatic

Question 27

What are electromagnetic waves

Answer 27

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

Question 28

Which waves are considered electromagnetic waves

Answer 28

``` Radio waves Microwaves Infrared radiation Light Ultra violet X-rays and gamma radiation ```

Question 29

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

Answer 29

Parallel | Do compress

Question 30

What waves are classed as longitudinal

Answer 30

Sound waves | Primary seismic waves

Question 31

Do transverse waves move parallel or perpendicular

Answer 31

They are perpendicular

Question 32

WHAT IS TOTAL INTERNAL REFLECTION?

Answer 32

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

Question 33

when can total internal reflection take place?

Answer 33

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.

Question 34

why is a laser used to produce light

Answer 34

so that the light produced is of the same frequency

Question 35

give a use of internal reflection

Answer 35

optical fibers

Question 36

what is the layer called that covers optical fibres?

Answer 36

Cladding

Question 37

What is an antinode?

Answer 37

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

Question 38

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

Answer 38

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.

Question 39

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

Answer 39

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

Question 40

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

Answer 40

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

Question 41

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

Answer 41

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

Question 42

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

Answer 42

The wavelength also increases.

Question 43

What is a coherent source?

Answer 43

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

Question 44

what is slit separation?

Answer 44

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

Question 45

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

Answer 45

Destructive interference.

Question 46

What safety precaution is needed when using a laser?

Answer 46

Never look directly into the light.

Question 47

Which waves are transverse

Answer 47

Electromagnetic Secondary seismic Waves on string or wire

Question 48

How do you know if a transverse wave is plane polarised

Answer 48

When vibrations stay in one plane only

Question 49

How do you know when a wave is unpolarised

Answer 49

When the wave moves to a different plane

Question 50

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

Answer 50

true

Question 51

What is an example of making a polarised wave

Answer 51

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

Question 52

Use of polarising light in real life

Answer 52

Sunglasses

Question 53

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

Answer 53

It won't go through

Question 54

What is the definition of displacement of vibrating particles

Answer 54

It's distance and direction from equilibrium position

Question 55

What is the amplitude of a wave

Answer 55

Maximum displacement of a vibrating particle

Question 56

What is the wavelength

Answer 56

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