Transcript Stellar Physics 1

Stellar Physics 1
Multiple Choice Questions
Test Question
Does this quiz work?
A. Yes
B. No
Stellar Physics 1
1. Which of the following stars are directly resolvable from earth with present
technology (including orbiting telescopes)?
A. The Sun only.
B. The Sun, Betelgeuse and Polaris.
C. The Sun, Betelgeuse and Alpha Centauri.
D. The Sun and Betelgeuse only. y
Stellar Physics 1
2. Fill in the blank: L = 4πD2 x __ .
A. 1/F.
B. F2.
C. 1/F2.
D. F. y
Stellar Physics 1
3. What is the approximate range of luminosities of stars other than the sun?
A. 10-4 Lsun < L < 106 Lsun. Y
B. 10-3 Lsun < L < 105 Lsun.
C. 10-2 Lsun < L < 106 Lsun.
D. 10-6 Lsun < L < 104 Lsun.
Stellar Physics 1
4. What are the units of the constant 0.0029 in Wien’s displacement law?
A. Milli-Kelvin.
B. W m-2.
C. metres / Kelvin.
D. metres Kelvin. y
Stellar Physics 1
5. To what power must the temperature be raised in the Stefan-Boltzmann
law?
A. 4.y
B. 3.
C. 2.
D. 1.
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6. What is the constant ‘σ’ in the relation L= 4πR2σT4?
A. Stefan-Boltzmann constant. Y
B. Boltzmann constant.
C. Wien constant.
D. Planck constant.
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7. Where do the white dwarfs lie on the Hertzprung-Russell diagram?
A. Bottom right.
B. Bottom left. Y
C. Top right.
D. Top left.
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8. Pogson’s can be used to relate…
A. Two absolute magnitudes with two fluxes.
B. Two apparent magnitudes with two luminosities.
C. Two fluxes with two apparent magnitudes. y
D. All of the above.
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9. Red giants are…
A. Cool and dim.
B. Cool and luminous. y
C. Hot and dim.
D. Hot and luminous.
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10. Which statement is correct?
A. White dwarfs can turn into main sequence stars.
B. White dwarfs can turn into red giants.
C. Red Giants can turn into main sequence stars.
D. Red giants can turn into white dwarfs. y
Stellar Physics 1
11. Cepheids are useful as distance indicators because of what relationship
they have?
A. Distance – luminosity relationship.
B. Temperature – luminosity relationship.
C. Temperature – distance relationship.
D. Luminosity – period relationship. y
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12. Which of the following is a correct form of Kepler’s third law?
A. T2/R3 = G(m1 + m2) / 4π2.
B. R3/T2 = G(m1 + m2) / 4π2. y
C. T2/R3 = G(m1m2) / 4π2.
D. R2/T3 = G(m1 + m2) / 4π2.
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13. Define the change in wavelength Δλ with relation to line-of-sight velocity v
due to the Doppler Effect:
A. Δλ = vc / λ0.
B. Δλ / c = v / λ0.
C. Δλ / λ0 = v / c. y
D. Δλ / λ0 = c / v.
Stellar Physics 1
14. Which of the following statements is true about eclipsing binary systems?
A. A secondary maximum occurs when a smaller star eclipses a larger star.
B. A primary minimum occurs when a smaller star eclipses a larger one.
C. A secondary minimum occurs when a smaller star eclipses a larger one.
D. A primary minimum occurs when a larger star eclipses a smaller one. y
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15. Which of the following is the correct sequence of the Harvard
classification scheme?
A. O, B, F, A, G, K, M.
B. O, B, A, G, K, F, M.
C. O, F, A, G, K, B, M.
D. O, B, A, F, G, K, M. Y
Stellar Physics 1
16. Which of the following is the incorrect statement about the Harvard
classification scheme?
A. O type stars are hotter than A type stars.
B. The Sun is a G type star.
C. M type stars are cool and luminous.
D. K type stars are hotter than G type stars. y
Stellar Physics 1
17. Which of the following statements is incorrect about a mass luminosity
relationship?
A. There is a mass luminosity relationship in all stars. y
B. There is a mass luminosity relationship but only in main sequence stars.
C. There is a mass luminosity relationship but only in red giants.
D. There is a mass luminosity relationship but only in white dwarfs.
Stellar Physics 1
18. Which of the following statements is incorrect?
A. A hot dense gas produces a continuous spectrum with no spectral lines.
B. A hot diffuse gas produces bright spectral lines – an emission spectrum.
C. A cool dense gas produces a continuous spectrum with no spectral lines. y
D. A cool diffuse gas in front of a source of continuous spectrum produces dark
spectral lines – an absorption spectrum.
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19. In the Bohr model, only photons with energies corresponding to
differences between energy levels can be emitted or absorbed, true or
false?
A. True. Y
B. False.
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20. In the Rydberg Equation, what is the expression R∞(1/m2 – 1/n2) equal to?
A. λ.
B. 1/ λ. Y
C. E.
D. 1/E.
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21. What is a Hayashi track?
A. The track that a star takes as it moves up the main sequence.
B. The track that a star takes as it moves down the main sequence.
C. The track that a star takes as it moves off the main sequence. y
D. The track that a star takes as it moves onto the main sequence.
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22. How is the sun predominantly powered?
A. Through p-p chain Hydrogen-Helium Fission.
B. Through the CNO cycle Hydrogen-Helium Fusion.
C. Through the CNO cycle Hydrogen-Helium Fission.
D. Through p-p chain Hydrogen-Helium Fusion. y
Stellar Physics 1
23. In the equation of hydrostatic equilibrium, how is the expression dP/dr
proportional to the radius ‘r’?
A. Directly proportional to r.
B. Inversely proportional to r.
C. Directly proportional to r2.
D. Inversely proportional to r2. y
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24. What is the mass luminosity relationship for main sequence stars?
A. L directly proportional to M3.5. y
B. L inversely proportional to M3.5.
C. M directly proportional to L3.5.
D. M inversely proportional to L3.5.
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25. Elements can only fuse in the core if there is a net drop in potential energy
of the protons during the reaction, after a certain point, corresponding to a
particular element, fusion stops producing energy and starts absorbing it
instead. What is this element?
A. Iron. y
B. Helium.
C. Hydrogen.
D. Titanium.