Chapter 12 - Waves

Question 1

2nd order maxima- path difference

Answer 1

2 λ

Question 2

2nd order minima- path difference

Answer 2

1.5 λ

Question 3

1st order maxima- path difference

Answer 3

λ

Question 4

1st order minima- path difference

Answer 4

λ/2

Question 5

central maxima

Answer 5

0

Question 6

2nd order maxima- phase difference

Answer 6

4π

Question 7

2nd order minima- phase difference

Answer 7

3π

Question 8

1st order maxima- phase difference

Answer 8

2π

Question 9

1st order minima- phase difference

Answer 9

π

Question 10

define path difference

Answer 10

The difference in distance travelled by each wave

Question 11

what does superpose mean

Answer 11

when 2 waves overlap

Question 12

What is the difference between interference and superposition

Answer 12

Superposition is the actual physical phenomena, but the interference is what we actually see. Interference is the pattern or effect that is observes by the superposition of waves.

Question 13

What happens if 2 waves are in phase when they meet?

Answer 13

This will double their maximum, causing a constructive interference.

Question 14

What happens if 2 waves are in antiphase when they meet?

Answer 14

They will completely cancel each other out, leaving a destructive interference.

Question 15

What happens if 2 waves are out of phase when they meet?

Answer 15

There will be a degree of destructive interference, but not total.

Question 16

How is intensity and amplitude related

Answer 16

Intensity = k * amplitude2 (squared)

Question 17

What is coherent waves

Answer 17

When 2 waves have the same frequency and they maintain the same phase difference.

Question 18

What is minima

Answer 18

Destructive interference

Question 19

What is maxima

Answer 19

Constructive interference

Question 20

How can you find the phase difference from the path difference

Answer 20

For 2 coherent wave differences, PLD as a fraction of the wavelength gives you the phase difference.

Question 21

Method to calculate the wavelength by using the path difference

Answer 21

Use a ruler to measure the path fro the centre of the first slit to the 1st order maxima. Do the same for the second slit to the maxima. Calculate the difference. The path difference at the 1st order maxima is 1 wavelength. Repeat for the rest of the maxima and minima. Average out the values for the wavelength.

Question 22

The Young Double Slit Experiment

Answer 22

It involves shining a light through a colour filter and then through a slit, which then shines it into 2 different slits. There 2 different slits create 2 coherent wave sources, which interfere as they overlap. Where they overlap on a screen, this is called the overlap region, where a pattern of alternating bright and dark ‘fringes’ can be seen.

Question 23

What is the name of the colour filter used in the Young Double Slit Experiment

Answer 23

A monochromatic filter

it only allows colours that are of a specific frequency

Question 24

How is a stationary wave created

Answer 24

It is formed when 2 waves (same frequency and hopefully amplitude) travelling in opposite directions superpose.

Question 25

What is a node

Answer 25

At certain points the 2 waves may be in antiphase, where their displacement cancels out. This point is called a node

Question 26

What is an antinode

Answer 26

The point at which the waves are at thier maximum amplitude

Question 27

The distance between 2 adjacent nodes is

Answer 27

half the wavelength

Question 28

In between 2 adjacent waves, how do the particles behave

Answer 28

all the particles oscillate with each other

Question 29

What happen to the particles on either side of a node

Answer 29

They are in antiphase to one another.

Question 30

The resultant force is

Answer 30

Basically the stationary force created.

Question 31

Energy transfer between a progressive wave and a stationary wave

Answer 31

P. Wave: energy transfer in the direction of the wave | S. Wave: no net energy transfer as the waves are moving in opposite direction

Question 32

Wavelength between a progressive wave and a stationary wave

Answer 32

P. Wave: minimum distance between 2 adjacent points on a wave that are in phase S. Wave: The distance from one node to the next times by 2.

Question 33

Phase difference between a progressive wave and a stationary wave

Answer 33

P. Wave: Phase changes across the complete cycle | S. Wave: All particles of the wave between 2 nodes are in phase and are in antiphase either side of the node.

Question 34

Amplitude between a progressive wave and a stationary wave

Answer 34

P. Wave: All parts of the wave have the same amplitude | S. Wave: Maximum amplitude occurs at the antinode

Question 35

Why will go through a filter

Answer 35

The plane of polarisation of the EM waves are parallel to the orientation of the filter, in such a way that no or very little light is absorbed.

Question 36

Why will light not go through the filter

Answer 36

The plane of polarisation of the EM waves is lined exactly perpendicular to the plane of the filter, meaning that all the light is absorbed.

Question 37

What is the refractive index

Answer 37

It is a ratio of between the speed of light in a vacuum and the speed of light in a given medium.

Question 38

Equation used to find the refractive index (n)

Answer 38

n = c/ v

Question 39

The greater the refractive index...

Answer 39

The more the light will refract.

Question 40

Refractive index equation according to Snell's Law

Answer 40

n = (sin i) / (sin r)

Question 41

Refractive index equation according to Snell's Law going from one medium into another

Answer 41

n1 (sin theta 1) = n2 (sin theta 2)

Question 42

What is Total Internal Reflection

Answer 42

A wave phenomenon by which light completely reflects back at a boundary between 2 media, as opposed to transmitting across the boundary and refracting back.

Question 43

What are the conditions for TIR

Answer 43

A medium within which light is incident has a larger refractive index, n, than a second medium. The incident ray must be more than the critical angle for TIR to occur.

Question 44

What is the derivation form of c

Answer 44

Root of t/μ.

Question 45

What can dictate the frequency of a string being plucked

Answer 45

Length Mass Tension

Question 46

Relationship between the frequency and the tension

Answer 46

Proportional. | If you pluck a string twice as hard, the frequency will increase by a factor of root 2

Question 47

What can dictate the frequency of a closed/ open air pipe stationary waves

Answer 47

Density Temperature Speed of the wave.

Question 48

By what multiples can closed air pipes work?

Answer 48

Only odd multiples of the fundamental

Question 49

By what multiples can open air pipes work?

Answer 49

Any multiples of the fundamental

Question 50

By what multiples can strings work?

Answer 50

Any multiples of the fundamental