Astrophysics
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Well.
- 1.What is an asteroid?
- A.
A very large collection of stars.
- B.
A stone.
- C.
A mixture of rock and ice orbiting the sun.
- D.
A small, minor planet that drifts in the solar system.
- 2.Why is the sun in equilibrium?
- 3.What is the luminosity of a star?
- A.
The work done per unit time
- B.
The energy emitted by unit time
- C.
The energy it emits a year
- D.
The brightness divided per area
- 4.What is the correct formula for apparent brightness?
- A.
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- B.
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- C.
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- 5.Which of the following statements are correct if stars are moving towards us?
- A.
Their wavelengths appear shorter
- B.
The light waves reaching us are more spaced out
- C.
The absorption lines appear blue-shifted
- D.
The absorption lines appear red-shifted
- 6.Binary stars can always be seen with the naked eye.
- A.
True
- B.
False
- 7.What can a stellar spectra be used for?
- 8.What is a stellar parallax?
- 9.What is true for the apparent magnitude?
- A.
Its symbol is little m
- B.
It's a celestial body's apparent brightness when viewed by an observer on Earth
- C.
It depends on luminosity and the distance of the star
- D.
It has the unit parcel (pc)
- E.
It has the unit light year (ly)
- 10.From the spectral class O to M:
- A.
The temperature increases
- B.
The temperature decreases
- C.
The temperature stays the same
- 11.Absolute magnitude is the apparent magnitude viewed 15 pc from Earth.
- A.
True
- B.
False
- 12.A star of known luminosity is called
- A.
A standard candle
- B.
A spectroscopic parallax
- C.
A cepheid
- 13.What is true for a cepheid?
- A.
Its luminosity varies exponentially with time
- B.
Its luminosity varies periodically with time
- C.
The outer layers of the star undergoes periodic expansion anf contraction
- D.
Due to the ionization of nitrogen there are variations in surface area and temperature
- 14.Spectroscopic parallax can be used to find the distance of a star, no matter how far away it is.
- A.
True
- B.
False
- 15.What is the critical density?
- 16.What is the mass density?
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