DP IB Physics: SL

Topic Questions

Syllabus Edition

First teaching 2014

Last exams 2024

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4.4 Wave Behaviour

1
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1 mark

Which phrase correctly completes the following sentence?

In a ray diagram showing reflection, the angle of incidence is the angle between

  • the incident ray and the boundary surface.

  • the incident ray and the normal.

  • the incident ray and the reflected ray.

  • the reflected ray and the boundary surface.

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2
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1 mark

Which property of a wave does not change as a result of refraction?

  • Frequency, f

  • Wavelength, λ

  • Wave speed in the medium, v

  • Amplitude, A

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3
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1 mark

Ray diagrams can be used to show the reflection, refraction and transmission of light at the boundary between media. 

4-4-q3-sl-easy-mcq-phy

In the diagram, what feature does X represent?

  • Reflected ray

  • Refracted ray

  • Transmitted ray

  • Incident ray

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4
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1 mark

A monochromatic laser beam is shone into the surface of a tank filled with water. The effects on the laser beam due to the water are observed.

How will the properties of the light be affected by the water?

 

speed

wavelength

frequency

A

no change

increases

decreases

B

decreases

decreases

no change

C

increases

decreases

no change

D

decreases

no change

increases

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5
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1 mark

When does diffraction occur?

  • In all waves

  • In soundwaves only

  • In transverse waves only

  • In light waves only

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6
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1 mark

Which image shows the correct ray diagram for light passing from air into water?

4-4-q6-sl-easy-mcq-phy

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7
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1 mark

The diagram shows a wave approaching an aperture.

4-4-q7-1-sl-easy-mcq-phy

Which diagram correctly shows the resulting diffraction pattern for the wave?

4-4-q7-sl-easy-mcq-phy

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8
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1 mark

Which row correctly describes the conditions for constructive and destructive interference in a double-slit diffraction pattern?

 

Constructive

Destructive

A.

Crest + crest

Trough + trough

B.

Crest + trough

Trough + trough

C.

Trough + trough Crest + crest

D.

Crest + crest

Crest + trough

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9
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1 mark

The diagram shows two waves. One wave is emitted from source s1 and travels to point P. The other wave is emitted from source s2 and travels to point P.

4-4-q9-sl-easy-mcq-phy

What is the path difference between the waves?

  • 1λ

  • 11 halfλ

  • 2λ

  • 21 halfλ

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10
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1 mark

The double-slit equation describes the relationship between the separation distance of the fringes on the screen, s, the distance between the screen and the slits, D, the separation of the slits, d, and the wavelength, λ, of the light. 

sfraction numerator lambda D over denominator d end fraction

Which line gives the correct units for the quantities?

 

s

D

λ

d

A.

m

m

m

m

B.

m−1

m

m s−1

m

C.

m m s−1 m m−1

D.

m2

m−1

m

m

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1
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1 mark

In a Young’s double-slit experiment, the spacing of the double slits is d and the distance between the slits and the screen on which fringes are formed is D. When monochromatic light of wavelength λ is incident on the slits the distance between adjacent fringes on the screen is s.

Which row shows another arrangement that produces a fringe spacing of s?

 

Wavelength of the light

Distance between the slits and the screen

Spacing of double Slits

A.

4 lambda

2D

4d

B.

2 lambda

2D

2d

C.

4 lambda

2D

2d

D.

4 lambda

2D

8d

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2
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1 mark

K is the source of a wave of frequency 25 Hz.

4-4-sl-mcq-hard-q2-phy

The wave travels to point M by two routes, K → L → M and K → M. The speed of the wave is 15 m s−1.

What is the path difference between the two waves at M in terms of the wavelength λ of the waves?

  • 4λ

  • 6.6λ

  • 31.6λ

  • 2.4λ

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3
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1 mark

The diagram below shows an arrangement used to investigate double slit interference using microwaves.

4-4-sl-mcq-hard-q3_1-phy

The diagram below shows the view from above:

4-4-sl-mcq-hard-q3_2-phy

The microwaves from the transmitter are polarised. These waves are detected by the aerial in the microwave detector (probe). The aerial is a vertical metal rod.

The detector is moved along the dotted line UY. As it is moved, maximum and minimum signals are detected. Maximum signals are first detected at points V and W. The next maximum signal is detected at the position X.

The distances between each of the two slits, S1 and S2 and the microwave receiver when the aerial is in position X are S1X = 0.3335 m and S2X = 0.3615 m

Select the three correct reasons that explain why the signal strength falls to a minimum between U and V, and between V and W.

 

Reason 1

Reason 2

Reason 3

A

Waves are out of phase

Gives rise to a path difference

Constructive interference occurs

B

Waves are out of phase

Gives rise to a path difference

Destructive interference occurs

C

Path difference for the two waves

Gives rise to a phase difference

Destructive interference occurs

D

Path difference for the two waves

Gives rise to a phase difference

Constructive interference occurs

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4
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1 mark

Our fingerprints are made up of a series of ridges on the end of the finger. These ridges can be ‘read’ by electronic devices.

The diagram below shows a certain type of fingerprint detector below, which works by scattering light when pressure is applied to a plastic screen. The ridges of the fingerprint press the plastic film against the glass when the finger is pressed to the screen.

4-4-sl-mcq-hard-q4_1-phy

When not in use, the plastic screen and the glass have a small air space between them. The diagram below shows the two possible paths for the light when the finger is pressed down.

4-4-sl-mcq-hard-q4_2-phy

Which row in the table correctly describes the properties of the fingerprint detector that cause the bright and dark patches on the image produced by the camera?

 

Bright

Dark

A.

glass and plastic have identical optical densities

glass and air have different optical densities 

B.

glass and plastic have different optical densities

glass and air have different optical densities 

C.

the plastic screen has a lower optical density than soft tissue in the finger

total internal reflection within the glass sends light rays to the camera

D.

the plastic screen and soft tissue in the finger have identical optical densities

identical optical densities between the glass and plastic prevent light from reaching the camera

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5
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1 mark

A sound source X1 is positioned w cm to the left of sound source X2. Both sound sources are y m below the detection line AB. AB runs parallel to X1X2 . When a sound detector is slowly moved along the line AB, a maxima is first detected at P, followed by a minima at Q, with another maxima at R and a minima at S. PQRS are all equidistant apart with X1 S = X2 S.

Which one of the following is a correct expression for the wavelength of the sound?

  • X1Q - X1P

  • X1R - X1Q

  • X1Q - X2Q

  • X1R - X2R

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6
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1 mark

A ray of light is incident on a material made from three layers, each having a different optical density, so that in each layer the light travels at a different speed.

  • For layer 1: refractive index = n1 and the speed of light = c1
  • For layer 2: refractive index = n2 and the speed of light = c2
  • For layer 3: refractive index = n3 and the speed of light = c3
  • Angle of incidence = i
  • Angle of refraction = r

This is illustrated in the diagram below:

4-4-sl-mcq-hard-q6-phy


Which is the correct expression for c3, the speed of light in the third layer?

  • fraction numerator c subscript 1 n subscript 1 over denominator n subscript 3 end fraction

  • fraction numerator c subscript 2 n subscript 2 over denominator c subscript 3 end fraction

  • fraction numerator c subscript 1 n subscript 1 over denominator blank n subscript 2 end fraction

  • fraction numerator c subscript 2 n subscript 2 over denominator s i n open parentheses r subscript 3 close parentheses end fraction

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7
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1 mark

Diamonds are highly valued because of their sparkle. This is caused by total internal reflection, which reflects most of the light that falls onto a cut diamond out of the face we see. Fake gems, called ‘paste’, are often used in jewellery because they are cheaper. However, paste gems sparkle much less than real diamonds.

The diagrams show a possible path of light through a real diamond, and another through a fake.

4-4-sl-mcq-hard-q7-phy

If:

  • n = refractive index;
    • nd is the refractive index of the diamond
    • nf is the refractive index of the fake
  • v = speed of light
    • vd is the speed of light in the diamond
    • v­­f is the speed of light in the fake

Which row in the table contains only statements which must be true?

 

Critical angle of diamond

 n subscript d over n subscript f

vd

A

Very small

> 1

< vf

B

Very small

< 1

> vf

C

Very large

> 1

< vf

D

Very large

< 1

> vf

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8
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1 mark

A double slit interference experiment is conducted using monochromatic light of wavelength λ. The centre of the observed pattern is a bright fringe.

4-4-sl-mcq-hard-q8-phy

What is the path difference between two waves which interfere to give the second dark fringe from the centre?

  • lambda

  • 1.5 lambda

  • 2.5 lambda

  • 3.5 lambda

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9
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1 mark

A student is investigating the interference of waves. They set up coherent waves produced at points S and T and travel outwards in all directions.

The line XY is halfway between S and T and perpendicular to the joining line S and T. The distance XY is much greater than the distance ST.

4-4-sl-mcq-hard-q9-phy

Which line or lines would an interference pattern be seen along?

  • WZ only

  • XY only

  • Both XY and WZ

  • Neither XY or WZ

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101 mark

When moving from material A to material B, the direction of a ray of light moves away from the normal. If nA and nB are the refractive indices of materials A and B respectively, then which of the following statements is true in this situation? 

  • The ratio of n subscript A over n subscript B is larger than one

  • The ratio of n subscript A over n subscript B is less than one

  • The ratio of n subscript A over n subscript B is exactly than one

  • The ratio of n subscript A over n subscript B cannot be known without more information

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11 mark

Two waves from individual point sources meet at a point X. Which of the following conditions is necessary for interference to be observed at point X?

  • Waves of equal amplitude

  • Waves of equal wavelength

  • A constant phase difference between the waves

  • The waves must be electromagnetic

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21 mark

This diagram below shows two apertures through which planar waves are passed as they are moving to the left. The wavefronts show crests moving in phase. Given this information, at which point will the amplitude of the waves be a minimum?

q12_wave-behaviour_ib-sl-physics-mcq

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31 mark

A flat plate made of glass has a refractive index of n = 1.52. What is the speed of light within this material? 

  • 1.36 × 108 m s–1

  • 1.67 × 108 m s–1

  • 1.97 × 108 m s–1

  • 2.66 × 108 m s–1

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41 mark

When a light ray enters a denser medium and refracts, some of the characteristics of the wave will change. Which of the following options is correct about this change?

 

Speed

Frequency

Wavelength

A

Increases

Decreases

Stays constant

B

Decreases

Stays constant

Decreases

C

Stays constant

Decreases

Increases

D

Increases

Increases

Stays constant

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51 mark

The effect of a double slit on monochromatic light is observed by the set up in the diagram below.

4-4-sl-mcq-hard-q10-phy

Interference fringes are seen on the screen.

Which of the following changes would increase the distance between the adjacent fringes?

  • Decrease the width of all the slits

  • Move the screen closer to the double-slit

  • Use light of a higher frequency

  • Decrease the distance between the two slits

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61 mark

Which of the following options will alter the frequency of a wave?

  • Reflection

  • Refraction

  • Diffraction

  • None of the above

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71 mark

Young’s double-slit experiment is setup as shown, including a monochromatic source, a single slit, a double slit and a screen. What is the purpose of the double slit in this experiment?

q17_wave-behaviour_ib-sl-physics-mcq

  • To make sure there is equal intensity in the double-slits

  • To make sure the light is coherent upon the double-slits

  • To decrease intensity for the double-slits

  • To reduce the wavelength of the light

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81 mark

Identical waves that begin propagation at the same time leave from two different sources and arrive at the same point – point X. The first source is 18 m from point X. The second source is 10.5 m from point X. The waves of both sources have a wavelength of 3 m. What is observed at X?

  • Complete destructive interference

  • Partial destructive interference

  • Partial constructive interference

  • Complete constructive interference

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91 mark

Which of the following images shown below best represents the path of visible light traveling through a glass prism?

q19_wave-behaviour_ib-sl-physics-mcq

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101 mark

The angle of incidence should always be measured between:

  • The normal and the reflected ray

  • The incident ray and the normal

  • The incident ray and the reflected ray

  • The incident ray and the surface of the second medium

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