Question 1a

Marks: 2

(a)

State the features of a single-slit diffraction pattern using monochromatic light.

[2]

Question 1b

Marks: 3

The monochromatic light is replaced by a source of white light.

(b)

The paragraph below describes how this change would affect the interference pattern. Choose appropriate words to fill the gaps.

[3]

The central maximum would be __________, and each subsidiary maximum would be composed of a ___________.

The ___________ wavelength would appear nearest to the central maximum, and the _____________ wavelength would appear furthest from the central maximum.

The fringe spacings would be ___________ and the maxima would be ____________.

Question 1c

Marks: 2

The white light source is replaced, first with red laser light and then blue laser light.

(c)

Explain the difference in the diffraction patterns between the red and blue light.

[2]

Question 1d

Marks: 2

The diagram below shows the intensity patterns for blue light.

$diffraction-graph-1$

(d)

On the same axes, sketch the intensity pattern for red light.

[2]

Question 2a

Marks: 1

The angle of diffraction of the first minima can be found using the following equation:

$θ = \frac{λ}{b}$

(a)

State the definition of each variable and give an appropriate unit for each.

[3]

Question 2b

Marks: 3

(b)

Use the equation from part (a) to determine what will happen to the angle of diffraction if the width of slit is doubled using monochromatic light.

[3]

Question 2c

Marks: 2

(c)

Use the equation from part (a) to explain why red light produces wider maxima than blue light.

[2]

Question 2d

Marks: 2

The graph below shows the diffraction pattern of monochromatic red light with a slit width b.

9-2-esq-2d-q-stem-1

(d)

Sketch on the same axes the diffraction pattern if the slit width was reduced.

[2]

Question 3a

Marks: 3

(a)

For the diffraction of light through a single slit, the following equation is used:

θ = \frac{λ}{b}

The equation contains some assumptions about the set up of the equipment.

(i)

Outline why the slit width has to be has to be smaller than the wavelength of the incident light.

[1]

(ii)

Explain why the screen must be placed a great distance away from the slit.

[2]

Question 3b

Marks: 4

(b)

Monochromatic light of wavelength 450 nm is incident upon a single slit of width 1.3 µm. Determine the angle of diffraction.

[4]

Question 3c

Marks: 1

(c)

State the colour of the light used in the experiment in part (b).

[1]

Question 3d

Marks: 2

(d)

Determine the angular width of the central maximum for the experiment in part (b).

[2]

Question 4a

Marks: 4

A group of students were conducting single-slit diffraction experiments with different coloured lasers.

(a)

A slit width of 0.12 mm was used, but the student forgot to note down what colour laser was used. The angle of diffraction produced was 0.0050 rad. Determine the colour of the incident light.

[4]

Question 4b

Marks: 4

(b)

The students decided to try the red laser next. Suggest, without calculation, how this would affect the diffraction pattern.

[4]

Question 4c

Marks: 3

(c)

Calculate the angle of diffraction using the red laser of wavelength 675 nm.

[3]

Question 4d

Marks: 7

(d)

Still using the same red laser, the students discussed the effect of decreasing the slit width by half.

(i)

State a prediction of the effect this would have on the diffraction pattern.

[3]

(ii)

Prove mathematically that your prediction would be correct.

[4]

Question 5a

Marks: 4

The following graph shows the diffraction pattern for monochromatic light incident on a single slit.

9-2-esq-5a-q-stem-1

(a)

The wavelength of the light used is 4.5 × 10⁻⁷ m. Calculate the width of the slit.

[4]

Question 5b

Marks: 3

The investigation from part (a) was repeated. The same light was used, but the slit width was doubled.

(b)

On the same graph shown in part (a) sketch the resulting diffraction pattern for the new slit width.

[3]

Question 5c

Marks: 4

(c)

Using the same light from parts (a) and (b), determine the slit width that would give the central maximum an angular width of 0.1 mrad.

[4]

Question 5d

Marks: 3

Light with wavelength λ is incident upon a single slit of width b producing an angle of diffraction θ.

(d)

Explain the change in the diffraction pattern if light with a wavelength

\frac{λ}{2}

and a slit width

\frac{b}{2}

were used.

[3]

DP IB Physics: HL

Topic Questions

9.2 Single-Slit Diffraction

Question 1a

Question 1b

Question 1c

Question 1d

Question 2a

Question 2b

Question 2c

Question 2d

Question 3a

Question 3b

Question 3c

Question 3d

Question 4a

Question 4b

Question 4c

Question 4d

Question 5a

Question 5b

Question 5c

Question 5d

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