Lesson 10.3.2

10.3.2 Age and ultimate fate of the universe Quiz: Pearson Edexcel Physics, Unit 10

20 questions

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Lesson 10.3.2, Age and ultimate fate of the universe: 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. Approximately what age does the Hubble constant give for the universe?

    • The age is about 1/H0.
    • The age is about H0.
    • The age is about H0 squared.
    • The age is about 1 / (H0 squared).

  2. What is the unit of the Hubble constant H0?

    • s^-1 Mpc^-1 km^2
    • Mpc s^-1
    • km s^-1 Mpc^-1
    • km s^-1

  3. How does dark matter affect the fate of the universe?

    • Its unseen mass adds to the gravitational attraction, which affects how strongly expansion is slowed.
    • It emits so much light that it prevents the universe from cooling.
    • It has no gravitational effect, so it cannot influence the fate of the universe.
    • It repels all matter, making the universe expand faster in every direction.

  4. In a closed universe with a density above the critical value, what is the eventual fate?

    • It expands forever at a constant speed.
    • It expands faster and faster forever.
    • It recollapses after expansion slows to a halt.
    • It remains exactly the same size for all time.

  5. If the Hubble time 1/H0 is about 14 billion years for H0 = 70 km s^-1 Mpc^-1, which value is closest to the Hubble time for H0 = 50 km s^-1 Mpc^-1?

    • about 2 billion years
    • about 200 billion years
    • about 20 billion years
    • about 5 billion years

  6. A Hubble constant estimate is revised so that H0 is doubled. What happens to the age estimate from 1/H0?

    • It doubles.
    • It halves.
    • It quadruples.
    • It stays the same.

  7. What is the approximate Hubble time for H0 = 70 km s^-1 Mpc^-1?

    • about 140 million years
    • about 1.4 trillion years
    • about 4.4 billion years
    • about 14 billion years

  8. What controversy about the age of the universe is linked to the value of the Hubble constant?

    • Galaxies are not moving, so the Hubble constant cannot be measured.
    • Different measurements of H0 give different expansion histories, so the estimated age and fate can differ.
    • Light from distant galaxies does not show any redshift at all.
    • The Hubble constant has been measured to be exactly the same for all observers.

  9. Why would extra unseen mass in the universe make a recollapse more likely?

    • The extra mass makes the Hubble constant equal to zero for every observer in space.
    • Extra gravity raises total density, which can halt the expansion.
    • The extra mass removes redshift from all distant galaxies so they no longer recede.
    • The extra mass repels galaxies, which speeds expansion up and makes the universe older.

  10. Which observation provided evidence that the expansion of the universe is accelerating?

    • Distant Type Ia supernovae look fainter than expected, implying accelerating expansion.
    • The Sun's luminosity has been found to vary measurably from year to year in all surveys.
    • Parallax angles are found to be exactly 1 arcsecond for all stars in the sky.
    • Nearby stars show a blueshift that is steadily increasing over many decades of observation.

  11. A flat universe with no dark energy would have an expansion that is

    • constant for all time
    • slowing down over time because of gravity
    • accelerating over time because of gravity
    • reversed at all times

  12. Why does the age estimate from 1/H0 only give an approximate value?

    • It assumes the expansion rate has been constant, but expansion has changed over time.
    • It assumes the Sun is the oldest object in the universe, which is well established.
    • It assumes the universe contains no stars at all, a statement that is clearly not true.
    • It assumes H0 is measured in light years per second, a unit choice that is incorrect here.

  13. Which statement about dark matter in the context of the universe's fate is correct?

    • It is a form of radiation that increases the expansion rate.
    • It is an unseen form of mass whose gravity affects the expansion history.
    • It has no effect on any measured property of the universe.
    • It is visible light emitted by distant galaxies.

  14. If a universe has an expansion rate that is slowed by gravity, what is the effect of more gravitational attraction on the time for the expansion to slow?

    • The expansion stops immediately.
    • The expansion slows more strongly and the universe may recollapse.
    • The expansion speeds up without any change.
    • The gravitational attraction has no effect on the expansion.

  15. A measured Hubble constant of 70 km s^-1 Mpc^-1 is compared with a value of 50. Which is the more likely consequence for the estimated age of the universe?

    • The age from the 50 value is larger, since age is about 1/H0.
    • The age from the 70 value is larger, since age is about H0.
    • The age from the 50 value is zero, since H0 is not a time.
    • Both ages are exactly the same, since H0 cancels out.

  16. Which statement about the Hubble constant is most accurate?

    • It relates the recession speed of galaxies to their distance, and its value is still debated.
    • It is the speed of light divided by the age of the universe.
    • It is a fixed number known exactly, and it does not need measurement.
    • It is the redshift of the nearest galaxy only.

  17. A galaxy is at a distance that makes its recession speed 14000 km s^-1 with H0 = 70 km s^-1 Mpc^-1. What is its distance?

    • 20 Mpc
    • 70 Mpc
    • 2000 Mpc
    • 200 Mpc

  18. Which quantity is the constant of proportionality in Hubble's law?

    • v
    • d
    • H0
    • z

  19. A galaxy lies at 500 Mpc. With H0 = 70 km s^-1 Mpc^-1, what is its recession speed?

    • 7000 km s^-1
    • 35000 km s^-1
    • 70000 km s^-1
    • 3500 km s^-1

  20. Why is the age of the universe inferred from H0 rather than read from a clock?

    • The age is always equal to the wavelength of the Hubble constant measured in km per second.
    • No clock was started at the Big Bang, so age must be inferred from expansion history.
    • Age is measured by counting the number of galaxies in the universe and dividing by H0.
    • Clocks do not work reliably on galaxies that are moving away from Earth at high speeds, so it fails.

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