Lesson 5.5.2

5.5.2 Diffraction gratings and the wavelength of light Quiz: Pearson Edexcel Physics, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.5.2, Diffraction gratings and the wavelength of light: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 5: Waves and Particle Nature of Light, written with Revision Ninja.

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The 20 questions

  1. What is the diffraction grating equation for maxima?

    • n lambda = d sin(theta)
    • n d = lambda sin(theta)
    • lambda = n d sin(theta)
    • n lambda = d tan(theta)

  2. In the diffraction grating equation nλ = d sinθ, what does d represent?

    • Slit width
    • Screen distance
    • Grating width
    • Slit spacing

  3. A grating has 500 lines per millimetre. What is the slit spacing d?

    • 5.0 micrometres
    • 0.5 micrometres
    • 20 micrometres
    • 2.0 micrometres

  4. What is the angle θ for the central zero-order maximum in a grating pattern?

    • 0 degrees
    • 45 degrees
    • 90 degrees
    • 180 degrees

  5. Compared to a double slit, how do bright maxima from a diffraction grating appear?

    • Fainter and wider
    • Sharper and brighter
    • Identical in sharpness
    • Broader and dimmer

  6. What is the maximum possible theoretical value of sinθ in the diffraction grating equation?

    • 1
    • Infinity
    • 0.5
    • 0

  7. When white light passes through a grating, which colour is deviated the most in each order?

    • Violet
    • Green
    • Red
    • Yellow

  8. A grating has slit spacing 2.0 micrometres. Light of wavelength 500 nm is used. What is the angle of the first-order maximum?

    • 30.0 degrees
    • 7.2 degrees
    • 25.0 degrees
    • 14.5 degrees

  9. A diffraction grating with spacing 2.0 micrometres gives a second-order maximum at 36.9 degrees. What is the wavelength of the light?

    • 300 nm
    • 1200 nm
    • 450 nm
    • 600 nm

  10. A grating has spacing 1.0 µm. What is the maximum order observed for 650 nm light?

    • 1
    • 4
    • 3
    • 2

  11. Light of wavelength 600 nm produces a first-order maximum at 30°. What is the line density?

    • 1200 lines/mm
    • 600 lines/mm
    • 833 lines/mm
    • 500 lines/mm

  12. A grating has slit spacing 2.5 micrometres. For light of wavelength 500 nm, what is the angle of the second-order maximum?

    • 36.9 degrees
    • 11.5 degrees
    • 53.1 degrees
    • 23.6 degrees

  13. A first-order maximum appears at 19.5 degrees from a grating of spacing 2.0 micrometres. What is the wavelength of the light?

    • 1000 nm
    • 340 nm
    • 670 nm
    • 520 nm

  14. A grating has 300 lines per millimetre. What is its slit spacing?

    • 3.3 micrometres
    • 300 micrometres
    • 0.30 micrometres
    • 33 micrometres

  15. A grating has spacing 3.0 micrometres. Light of wavelength 600 nm is used. What is the angle of the third-order maximum?

    • 18.4 degrees
    • 65.4 degrees
    • 53.1 degrees
    • 36.9 degrees

  16. How does the diffraction angle θ of a maximum change as wavelength increases?

    • Angle increases
    • Angle becomes zero
    • Angle stays constant
    • Angle decreases

  17. A grating's first-order maximum for light of wavelength 633 nm appears at 25.0 degrees. What is the slit spacing?

    • 0.67 micrometres
    • 2.5 micrometres
    • 1.5 micrometres
    • 3.5 micrometres

  18. A grating of spacing 2.0 micrometres is used with white light. What is the approximate angular separation of the first-order maxima for 400 nm and 700 nm light?

    • About 17 degrees
    • About 4.5 degrees
    • About 9.0 degrees
    • About 12 degrees

  19. Why are principal maxima from a diffraction grating sharper than those from a double slit?

    • Multiple slit interference
    • Smaller wave energy
    • Greater light speed
    • Higher wave frequency

  20. What colour is observed at the zero-order maximum when white light passes through a grating?

    • Red light
    • Violet light
    • Continuous spectrum
    • White light

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