Lesson 5.5.2

5.5.2 Electromagnetic radiation from stars Quiz: OCR Physics, Unit 4

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 5.5.2, Electromagnetic radiation from stars: 20 multiple choice questions for the OCR Physics (H156), Unit 4: Newtonian world and astrophysics, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. Why are electron energy levels in isolated gas atoms assigned negative values?

    • Zero potential energy
    • Free electron state
    • Positive kinetic energy
    • Bound electron state

  2. How is an emission line produced when an electron transitions between energy levels?

    • Emits a photon
    • Gains kinetic energy
    • Absorbs a photon
    • Emits a proton

  3. Which equation correctly links photon energy change to frequency for an electron transition?

    • Delta E = h/f
    • Delta E = hc/f
    • Delta E = hf
    • Delta E = f/h

  4. Why can spectral lines be used to identify elements present in a star?

    • Unique energy levels
    • Unique mass numbers
    • Constant temperature
    • Identical wavelengths

  5. What feature characterises an absorption line spectrum produced by stellar atmospheres?

    • Discrete bright lines only
    • Bright lines on dark
    • Dark lines on continuous
    • Uniform continuous spectrum

  6. In the grating equation d sin theta = n lambda, what does d represent?

    • Grating element spacing
    • Order number
    • Slit length
    • Screen distance

  7. What mathematical condition determines the maximum observable order number for a diffraction grating?

    • Sin theta is one
    • Tan theta is zero
    • Path difference is zero
    • Cos theta is one

  8. How does the peak emission wavelength of a star change as its temperature increases?

    • Increases
    • Stays constant
    • Decreases
    • Doubles exponentially

  9. By what factor does a star's luminosity increase if its surface temperature doubles?

    • Factor of 8
    • Factor of 16
    • Factor of 2
    • Factor of 4

  10. What produces a continuous spectrum of electromagnetic radiation from a star?

    • Hot dense core
    • Cool outer atmosphere
    • Free electrons only
    • Low density gas

  11. Which formula gives the wavelength of a photon emitted during an energy transition Delta E?

    • lambda = c Delta E / h
    • lambda = h / (c Delta E)
    • lambda = hc / Delta E
    • lambda = h Delta E / c

  12. In the diffraction grating formula d sin theta = n lambda, what does n represent?

    • Wavelength ratio
    • Order of maximum
    • Number of slits
    • Refractive index

  13. A grating has 500 lines per millimetre. What is its line spacing d in metres?

    • 5 x 10^-4 m
    • 2 x 10^-6 m
    • 5 x 10^-6 m
    • 2 x 10^-3 m

  14. What type of spectrum consists of isolated bright lines against a dark background?

    • Continuous spectrum
    • Emission line spectrum
    • Blackbody spectrum
    • Absorption line spectrum

  15. Which two values are required alongside Stefan constant to calculate a star radius?

    • Distance and parallax
    • Wavelength and frequency
    • Mass and density
    • Luminosity and temperature

  16. What does an electron energy level of zero joules represent in an atom?

    • Ground state electron
    • Proton in nucleus
    • Free electron
    • Minimum possible energy

  17. According to Wien displacement law, what product remains constant for any blackbody radiator?

    • Lambda max times T
    • Frequency times lambda
    • Intensity times area
    • Power times temperature

  18. An electron drops by 3.0 x 10^-19 J. What frequency photon is emitted?

    • 6.63 x 10^14 Hz
    • 1.98 x 10^-52 Hz
    • 2.22 x 10^14 Hz
    • 4.5 x 10^14 Hz

  19. What happens to an atomic electron when an absorption spectrum line is formed?

    • Emits a photon
    • Moves to higher level
    • Moves to lower level
    • Escapes the nucleus

  20. What equation represents Stefan's law for a spherical star of radius r?

    • L = 4 pi r sigma T^2
    • L = 4 pi r^2 sigma T^4
    • L = 4 pi r^3 sigma T^4
    • L = pi r^2 sigma T^4

All OCR Physics quizzes