AQA AS Physics

Topic Questions

3.4 Diffraction

11 mark

What is the correct definition of wave diffraction?

  • When a wave is returned from it’s original direction when incident on a shiny surface

  • The change in direction of a wave when it passes between materials of different density

  • The spreading out of waves when they pass an obstruction

  • The constructive interference of two waves in phase

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21 mark

What is the correct definition of a diffraction pattern?

  • Light can be represented as a series of light and dark fringes which show the areas of maximum and minimum intensity

  • The ripples visible on the surface of the water when water waves are diffracted

  • The change in amplitude of a wave as it passes through a gap in a barrier

  • The spectrum formed when white light is passed through a prism

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31 mark

For a plane transmission diffraction grating, the diffraction grating equation for the first order beam is:

d sin(θ) = λ

The figures below show two of the slits in the grating. Which figure shows the correct distance for λ?

q3_diffraction_aqa-as-physics-mcq

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41 mark

Diffraction gratings have a wide range of uses in science and medicine.

Which of the following answers contain four correct uses of diffraction gratings?

 

Use 1

Use 2

Use 3

Use 4

A

Analyse Light from stars

Analyse the absorption spectra in stars

Analyse the signals received in a piezoelectric crystal

Analyse the frequency of sound coming from oceanic mammals

B

Analyse composition of stars

X-Ray crystallography

Analyse the dust particles of a comet

Measure the wavelength of light from a star

C

Chemical analysis of stars

Measure the rotational frequency of a star

Measure rotation of a planet

Measure the velocity of a comet travelling towards Earth

D

Measure red shift

Measure the frequency of light from a star

Analyse the emission spectra in stars

Observe the spectra of materials

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51 mark

The diagram shows a diffraction grating and a monochromatic source of light with wavelength (λ).

q5_diffraction_aqa-as-physics-mcq

What happens to the angle of diffraction (θ) when the wavelength of light is increased, but all the other equipment remains the same?

  • The angle of diffraction remains the same

  • The angle of diffraction is decreased

  • The angle of diffraction is increased

  • There is not enough information to know what will happen

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61 mark

The diagram shows a diffraction grating with a slit distance (d) and a monochromatic source of light incident on the grating.

q6_diffraction_aqa-as-physics-mcq

What happens to the angle of diffraction when the distance between the slits on the grating is reduced?

  • The angle of diffraction remains the same

  • The angle of diffraction is decreased

  • The angle of diffraction is increased

  • There is not enough information to know what will happen

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71 mark

A diffraction pattern is formed by passing monochromatic light through a single slit.

If the width of the single slit is reduced, which of the following is true?

 

Intensity of central maximum

Width of central maximum

A

decreases

increases

B

decreases

decreases

C

unchanged

decreases

D

increases

increases

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81 mark

What is the correct description of a diffraction grating?

  • A plate on which there is a single slit of a specified width

  • A transparent thin film through which only polarised light can pass

  • A small block of glass used for optical experiments

  • A plate on which there is a very large number of parallel, identical, close-spaced slits

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91 mark

The diagram below shows a spectrometer that uses a diffraction grating to split a beam of white light into its constituent wavelengths and enables to angles of these diffracted beams to be measured.

q9_diffraction_aqa-as-physics-mcq

Which of the following statements about the light emerging at A and B is true?

 

Statement 1

Statement 2

A

The intensity of light at A will be less than at B

The light at B will appear white

B

The intensity of the light at A will be greater than at B

There will be a spectrum at B

C

The intensity of the light at A will be greater than at B

There will be a spectrum at A

D

There will be red light appearing at A

There will be a violet light appearing at B

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101 mark

Which is a description of the pattern produced when monochromatic light passes through a very narrow slit?

  • A narrow central maximum with wider side fringes

  • A wide central maximum with narrower fringes at the side

  • A narrow central maximum with wider fringes at the side, getting wider the further away from the central maximum

  • A small number of bright fringes that are spaced far apart

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11 mark

The figure below shows a spectrometer that uses a diffraction grating to split a beam of light into its constituent wavelengths and enables the angles of the diffracted beams to be measured.

q21_diffraction_aqa-as-physics-mcq

Light with a particular wavelength is passed through the diffraction grating. The angle of diffraction θ at the centre of the observed beam at Z in the image above is 63.0⁰ and the grating has 1562 lines per mm.

A dark fringe is observed at position W, with the central maxima at the straight through position.

How many orders of maxima of this light are present at this wavelength?

  • 2

  • 3

  • 1

  • 0

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21 mark

This question is about the measurement of the wavelength of laser light.

The light is shone onto a diffraction grating at normal incidence.

The light transmitted by the diffraction grating produces five spots on a screen. These spots are labelled P to T as shown in the diagram below.q22_diffraction_aqa-as-physics-mcq

A student uses a meter ruler with 1 mm divisions to take readings. She uses these readings to obtain the measurements x, y and z the distances between centres of the spots.

The table shows her measurements and her estimated uncertainties.

Measurement Distance / mm Uncertainty / mm
x 289 2
y 255 2
z 544 2

The distance between the centres of spots P and R and the distance between the centres of R and T are equal.

That is:

x + y = z

What is the percentage uncertainty in the sum of x and y?

  • 0.74 %

  • 1.48 %

  • 74 %

  • 1.47 %

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31 mark

Monochromatic electromagnetic radiation of wavelength 3.2 x 10-7 m is incident normally on a diffraction grating with 5.0 x 105  lines per meter.

What is the highest order maximum produced?

  • 7

  • 6

  • 5

  • 4

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41 mark

A discharge lamp emits light of four colours: red ( λ = 665 nm), green ( λ = 550 nm), blue ( λ = 470 nm) and violet ( λ = 400 nm). The diagram shows light from the lamp incident normally on a diffraction grating with 0.8 x 103 slits per millimeter. The light is viewed through a telescope that can be rotated as shown.

q24_diffraction_aqa-as-physics-mcq

As the telescope is rotated from the straight through position, each of the four colours is observed as a bright line at its corresponding first-order diffraction angle.

How many additional order of maxima will be seen with this set up for the colour that is observed furthest away from the central maxima?

  • 3

  • 2

  • 1

  • 0

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51 mark

A diffraction grating is illuminated normally with light of wavelength 5.5 x 10-7m.

When a screen is 1.2 m from the grating, the distance between the zero and first-order maxima on the screen is 0.40 m.

q25_diffraction_aqa-as-physics-mcq

What is the number of lines per mm of the diffraction grating?

  • 1.7 x 10-6

  • 3.5 x 1010

  • 588

  • 588 x 103

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61 mark

Light of wavelength 650 nm is incident on a diffraction grating which has 500 lines per mm.

What is the angular separation between the two second-order maxima?

  • 81.0⁰

  • 40.5⁰

  • 0.074⁰

  • 37.9⁰

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71 mark

A parallel beam of monochromatic light is directed normally at a plane of transmission grating which has N slits per meter.

The second order diffracted beam is at an angle θ to the zero-order transmitted beam.

 q27_diffraction_aqa-as-physics-mcq

The grating is then replaced by a plane transmission grating which has 4N slits per meter.

Which one of the following statements is correct?

  • With the first grating, the first order beam is at an angle of 0.25θ to the zero-order transmitted beam

  • With the second grating, the second order beam is at an angle of 0.25θ to the zero-order transmitted beam

  • With the second grating, the first order beam is at an angle of θ to the zero-order transmitted beam

  • With the second grating, the second order beam is at an angle θ to the zero-order transmitted beam

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81 mark

Light of wavelength λ is incident normally on a diffraction grating for which adjacent lines are a distance 5 λ apart. What is the angle between the third order maximum and the straight-through position?

  • 24⁰

  • 53⁰

  • 37⁰

  • There is no third order maximum

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91 mark

A diffraction grating was used to measure the wavelength of a certain line of a light emission spectrum.

The grating had 500 lines per millimeter. The angle of diffraction of the third order line was 25.3⁰.

What is the energy in eV of a photon of this wavelength?

  • 4.42

  • 7.07 x 10-19

  • 2.8 x 10-7

  • 1.74 x 10-8

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101 mark

Figure 1 shows a laser beam of wavelength 550 nm incidental normally on a diffraction grating.

The LDR of a scanning photometer is moved across the diffracted beam and produces the scan shown in Figure 2.This shows the central bright fringe with one further maximum (the first order image) on each side of it. The distance from the diffraction grating to the LDR is 150 mm.

Figure 1

q30_diffraction_aqa-as-physics-mcq

Figure 2

q30_2_diffraction_aqa-as-physics-mcq

What is the number of lines per mm on the diffraction grating?

  • 158 730

  • 159

  • 2.1 x 10-10

  • 6.3 x 10-6

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11 mark

A diffraction grating with 1000 lines per cm has light passed through it. An identical light source is also passed through two slits 0.5 mm apart.

Both will produce intensity maxima and minima on a screen.

Which of the following statements about the separation and sharpness of the maxima is correct?

  • The diffraction grating maxima are more widely spaced and are less sharp than the two-slit maxima

  • The diffraction grating maxima are less widely spaced and are sharper than the two-slit maxima

  • The diffraction grating maxima are more widely spaced and are sharper than the two-slit maxima

  • The diffraction grating maxima are less widely spaced and are less sharp than the two-slit maxima

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21 mark

A beam of monochromatic light is directed at a diffraction grating as shown in the diagram

q12_diffraction_aqa-as-physics-mcq

Which of the following diagrams show the possible directions of the light that will give maximum intensity?

q12-1_diffraction_aqa-as-physics-mcq

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31 mark

Monochromatic light with a wavelength of 600 nm is observed through a diffraction grating with 500 lines per mm.

The light is passed through a narrow slit where the lines from the slit are parallel to the grating. The light goes through the slit then the grating.

q13_diffraction_aqa-as-physics-mcq

The observer changes position from R (parallel with the grating), then S (opposite the slit) and finally T (parallel to the grating on the opposite side).

What is the number of images they would see in total?

  • 7

  • 6

  • 4

  • 3

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41 mark

Yellow light with a wavelength of 600 nm is used in a diffraction grating experiment. The grating has a separation of 2.00 μm.

q14_diffraction_aqa-as-physics-mcq

What would be the angular separation between the first order and second order maxima?

  • 56.3º

  • 36.9º

  • 19.4º

  • 17.5º

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51 mark

Monochromatic light of wavelength 650 nm is incident normally on a plane diffraction grating having 7 × 105 lines m–1. An interference pattern is produced. What is the highest order visible in this interference pattern?

  • 2

  • 3

  • 4

  • 5

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61 mark

A beam of monochromatic light with a wavelength of 690 nm is directed at a diffraction grating with 300 lines per mm as shown in the diagram

q16_diffraction_aqa-as-physics-mcq

This set up produces a series of maxima on the screen, what is the greatest number that can be observed?

  • 9

  • 8

  • 5

  • 4

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71 mark

A diffraction grating was used with a spectrometer to obtain the line spectrum of star P as shown in the figure below. The figure shows some line spectra for six elements that have been obtained in the laboratory.

q17_diffraction_aqa-as-physics-mcq

Which of the following answer options shows the three elements present in the atmosphere of star P?

A

Strontium

Calcium

Sodium

B

Mercury

Helium

Hydrogen

C

Strontium

Helium

Hydrogen

D

Mercury

Calcium

Sodium

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81 mark

A single slit diffraction pattern is produced on a screen using a blue laser. The intensity of the central maximum is plotted on the axes in the figure below.

q18_diffraction_aqa-as-physics-mcq

The laser is replaced with a ray box and lamp that produces a narrow beam of white light.

Which of the following describes the appearance of the fringes as they would be seen on a screen?

 

Statement 1

Statement 2

Statement 3

Statement 4

A

Equally high fringes of light are present across the screen

Single colours of the spectrum are present at each subsidiary maxima

Central maxima is a spectrum from red to violet

Violet is present on the outer edge of the subsidiary maxima

B

Distinct fringes at each subsidiary maxima

White light is present at each subsidiary maxima

Central maxima is a spectrum from red to violet

Red is present on the outer edge of the subsidiary maxima

C

Equally high fringes of light are present across the screen

White light is present at each subsidiary maxima

Central maxima is white

Violet is present on the outer edge of the subsidiary maxima

D

Distinct fringes at each subsidiary maxima

All colours of the spectrum are present at all subsidiary maxima

Central maxima is white

Violet is present on the inner edge of the subsidiary maxima

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91 mark

The diagram below shoes a laser emitting orange light directed at a single slit, where the slit width is greater than the wavelength of the light. The intensity graph for the diffracted orange light is shown.

q19_diffraction_aqa-as-physics-mcq

The laser is replaced by a laser emitting green light.

Which option shows how the intensity varies with position for the orange and green light sources on the screen?

ma19_diffraction_aqa-as-physics-mcq

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101 mark

A diffraction grating has 200 lines per mm. It is illuminated with monochromatic light of wavelength 650 nm.

What is the angle of the second order maximum?

  • 0.015 ⁰

  • 15.1 ⁰

  • 3.72 x 10 to the power of negative 7 end exponent

  • 7.47 ⁰

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