Lesson 10.1.2

10.1.2 Measuring astronomical distances Quiz: Pearson Edexcel Physics, Unit 10

20 questions

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Lesson 10.1.2, Measuring astronomical distances: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 10: Space, written with Revision Ninja.

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The 20 questions

  1. Which equation relates the parallax angle p in arcseconds to distance d in parsecs?

    • d = p
    • d = 1 / p in degrees
    • d = p^2
    • d = 1 / p

  2. What parallax angle defines a stellar distance of exactly one parsec?

    • One arcsecond
    • One degree
    • One arcminute
    • One radian

  3. Why is trigonometric parallax unsuitable for measuring distances to very distant stars?

    • Interstellar absorption
    • Luminosity changes
    • Angle too small
    • Stars move faster

  4. What property of an astronomical object must be known to use it as a standard candle?

    • Luminosity
    • Radius
    • Surface temperature
    • Mass

  5. A star has parallax 0.50 arcsec. What is its distance?

    • 0.5 pc
    • 5 pc
    • 2 pc
    • 0.2 pc

  6. A star has parallax 0.25 arcsec. What is its distance?

    • 4.0 pc
    • 0.8 pc
    • 0.25 pc
    • 13 pc

  7. A star is at 10 pc. What is its distance in metres, using 1 pc = 3.09 x 10^16 m?

    • 3.1 x 10^18 m
    • 1.0 x 10^17 m
    • 3.1 x 10^16 m
    • 3.1 x 10^17 m

  8. A Cepheid-type standard candle has luminosity 4.0 x 10^26 W and intensity 2.0 x 10^-9 W m^-2 at Earth. What is its distance?

    • 1.3 x 10^14 m
    • 6.3 x 10^16 m
    • 2.5 x 10^17 m
    • 1.3 x 10^17 m

  9. A parallax of 0.05 arcsec gives a distance of 20 pc. If the measurement uncertainty in parallax is 0.01 arcsec, what is the fractional uncertainty in the parallax?

    • 20%
    • 5%
    • 0.2%
    • 2%

  10. How many light years is 10 pc, using 1 pc = 3.26 light years?

    • 326 light years
    • 3.26 light years
    • 32.6 light years
    • 1.0 light year

  11. Two stars have the same luminosity. The brighter star has nine times the intensity of the fainter star at Earth. What is the ratio of the brighter star's distance to the fainter star's distance?

    • 9:1
    • 1:9
    • 3:1
    • 1:3

  12. How does uncorrected interstellar dust affect distance estimates made using standard candles?

    • No effect
    • Underestimates distance
    • Overestimates distance
    • Halves distance

  13. A star has parallax 0.10 arcsec and apparent intensity 1.0 x 10^-10 W m^-2 at Earth. What is its luminosity?

    • 1.2 x 10^24 W
    • 1.2 x 10^26 W
    • 3.0 x 10^26 W
    • 9.5 x 10^25 W

  14. If the trigonometric parallax angle of a star is halved, what happens to its calculated distance?

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

  15. Why are standard candles useful for determining distances to very distant galaxies?

    • High temperature
    • Large parallax
    • High velocity
    • Known luminosity

  16. Which quantity is measured directly when determining stellar parallax?

    • Luminosity
    • Parallax angle
    • Absolute magnitude
    • Radiant flux

  17. Which value is used with Earth's orbital radius to calculate distance by trigonometry?

    • Parallax angle
    • Peak wavelength
    • Redshift
    • Apparent brightness

  18. A star is at 2.5 pc. What is its parallax angle in arcseconds?

    • 4.0 arcsec
    • 2.5 arcsec
    • 0.40 arcsec
    • 0.025 arcsec

  19. What is the main advantage of standard candles over trigonometric parallax?

    • Greater measurable distances
    • Simpler calculations
    • Higher accuracy
    • Independent of brightness

  20. A standard candle has luminosity 2.0 x 10^27 W. Its measured intensity is 2.0 x 10^-8 W m^-2. What is its approximate distance?

    • about 4.0 x 10^18 m
    • about 1.3 x 10^18 m
    • about 6.3 x 10^17 m
    • about 1.3 x 10^16 m

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