Lesson 3.3.2.2

3.3.2.2 Diffraction Quiz: AQA Physics, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.2.2, Diffraction: 20 multiple choice questions for the AQA Physics (7408), Unit 3: Waves, written with Revision Ninja.

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The 20 questions

  1. What term describes the spreading of waves as they pass through a narrow gap?

    • Polarisation
    • Superposition
    • Diffraction
    • Refraction

  2. When is diffraction of a wave passing through a gap most significant?

    • Gap much larger
    • Gap is zero
    • Gap equals wavelength
    • Gap exceeds wavelength

  3. What is observed at the centre of a single-slit diffraction pattern using white light?

    • White bright fringe
    • Dark central fringe
    • Red bright fringe
    • Rainbow spectrum

  4. What happens to the width of the central diffraction maximum when the slit is made narrower?

    • It becomes wider
    • It is unchanged
    • It disappears completely
    • It becomes narrower

  5. What is the diffraction grating equation for maxima at normal incidence?

    • d sin(theta) = n λ
    • d sin(theta) = λ/n
    • d = n λ sin(theta)
    • d cos(theta) = n λ

  6. In the diffraction grating equation d sin θ = nλ, what does d represent?

    • Slit width
    • Screen distance
    • Slit spacing
    • Order number

  7. Which device uses a diffraction grating to separate light into component wavelengths?

    • Microscope
    • Polarimeter
    • Refractometer
    • Spectrometer

  8. A grating has spacing d = 2.0 μm. What is the angle of the first-order maximum for λ = 500 nm?

    • 14.5 degrees
    • 7.2 degrees
    • 30 degrees
    • 45 degrees

  9. A grating has spacing d = 2.0 μm. What is the angle of the second-order maximum for λ = 400 nm?

    • 23.6 degrees
    • 0.4 degrees
    • 47.2 degrees
    • 11.5 degrees

  10. A grating has spacing d = 2.0 μm. What is the highest order visible for λ = 700 nm?

    • 4
    • 1
    • 2
    • 3

  11. A grating has spacing d = 1.0 μm. What is the first-order angle for λ = 500 nm?

    • 30 degrees
    • 45 degrees
    • 15 degrees
    • 60 degrees

  12. How does doubling the single slit width affect the width of the central maximum?

    • It quadruples
    • It halves
    • It stays constant
    • It doubles

  13. A grating has spacing d = 2.0 μm. A first-order maximum is seen at 20 degrees. What is the wavelength?

    • 684 nm
    • 1.00 μm
    • 342 nm
    • 6.8 nm

  14. Why are diffraction grating maxima sharper than single-slit maxima?

    • Wider single slit
    • Higher light speed
    • Greater light intensity
    • More interfering slits

  15. Why does sound diffract more noticeably through doorways than light does?

    • Transverse nature
    • Longer wavelength
    • Slower speed
    • Higher frequency

  16. Which wave diffracts more through a 2 cm gap: sound of wavelength 2 m, or light of wavelength 600 nm?

    • they diffract equally
    • neither diffracts
    • the sound
    • the light

  17. If the line spacing of a grating decreases (d gets smaller), what happens to the angle of a given order?

    • It decreases
    • It is unchanged
    • It increases
    • It becomes zero

  18. In single-slit diffraction, at what condition does the first minimum occur?

    • a sin θ = λ/2
    • a sin θ = λ
    • a sin θ = 2λ
    • a sin θ = 0

  19. If the wavelength is doubled for a fixed grating and first order, what happens to sin θ?

    • It is unchanged
    • It doubles
    • It halves
    • It quadruples

  20. Why does a diffraction grating split white light into a spectrum?

    • Angle varies with wavelength
    • Intensity varies with wavelength
    • Amplitude depends on colour
    • Speed varies with frequency

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