# Astronomy college course/Introduction to stellar measurements/questions

Astronomy_college_course#Introduction_to_stellar_measurements
* answers
* Equations
* Supplement (better version of certain questions for conversion to quizbank)

## AstroStellarMeasurements_Study

Template:EduV/quizedit
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### AstroStellarMeasurements_Study-v1s1

1. Stellar parallax is
    ___ a) a numerical measure of brightness as seen from Earth
    ___ b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    ___ c) an annual change in angular position of a star as seen from Earth
    ___ d) an astronomical object with known luminosity.
    ___ e) the total amount of energy emitted per unit time.
2. Luminosity is
    ___ a) an annual change in angular position of a star as seen from Earth
    ___ b) a numerical measure of brightness as seen from Earth
    ___ c) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    ___ d) an astronomical object with known luminosity.
    ___ e) the total amount of energy emitted per unit time.
3. A standard candle is
    ___ a) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    ___ b) a numerical measure of brightness as seen from Earth
    ___ c) an astronomical object with known luminosity.
    ___ d) an annual change in angular position of a star as seen from Earth
    ___ e) the total amount of energy emitted per unit time.
4. Absolute magnitude is
    ___ a) a numerical measure of brightness as seen from Earth
    ___ b) the total amount of energy emitted per unit time.
    ___ c) an annual change in angular position of a star as seen from Earth
    ___ d) an astronomical object with known luminosity.
    ___ e) a numerical measure of brightness as seen from a distance of approximately 33 light-years
5. Relative magnitude is
    ___ a) a numerical measure of brightness as seen from Earth
    ___ b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    ___ c) an astronomical object with known luminosity.
    ___ d) an annual change in angular position of a star as seen from Earth
    ___ e) the total amount of energy emitted per unit time.
6. In 1989 the satellite Hipparcos was launched primarily for obtaining parallaxes and proper motions allowing measurements of stellar parallax for stars up to about 500 parsecs away, which is about ____ times the diameter of the Milky Way Galaxy.
    ___ a) 15
    ___ b) 1.5
    ___ c) 150
    ___ d) .015
    ___ e) 0.15
7. An object emits thermal (blackbody) radiation with a peak wavelength of 250nm. How does its temperature compare with the Sun?
    ___ a) 5 times colder than the Sun
    ___ b) 2 times colder than the Sun
    ___ c) 5 times hotter than the Sun
    ___ d) The temperature is the same
    ___ e) 2 times hotter than the Sun
8. The "normalized intensity" of a Sun-like star situated one parsec from Earth would be 4πI = 1. What is 4πI for a star with 100 times the Sun's energy output that is situated 10pc from Earth?
    ___ a) 10$^{-2}$
    ___ b) 10$^{-3}$
    ___ c) 10$^{-1}$
    ___ d) 1
    ___ e) 10$^{-4}$
9. An orbiting satellite makes a circular orbit 5 AU from the Sun. It measures a parallax angle of 0.2 of an arcsecond (each way from the average position). What is the star's distance?
    ___ a) 25 parsecs
    ___ b) 5 parsecs
    ___ c) 50 parsecs
    ___ d) 1 parsec
    ___ e) 10 parsecs
10. A star that is increasing it's temperature while maintaining constant luminosity is
    ___ a) getting smaller in size
    ___ b) on the verge of becoming a supernovae
    ___ c)e) getting larger in size
    ___ d) in the process of dying
    ___ e) turning red
11. The range of wavelength for visible light is between
    ___ a) 5000 and 6000 nanometers
    ___ b) 1 and 10 nanometers
    ___ c) 600 and 1200 nanometers
    ___ d) 400 and 700 nanometers
    ___ e) 0.1 and 10 nanometers
12. Based on the HR diagrams and images in stars shown in the materials, a very large red supergiant has a diameter that is about ____ greater than a small white dwarf.
    ___ a) 3x10$^7$
    ___ b) 3x10$^9$
    ___ c) 3x10$^5$
    ___ d) 3x10$^{11}$
    ___ e) 3x10$^3$

#### Key to AstroStellarMeasurements_Study-v1s1

1. Stellar parallax is
    - a) a numerical measure of brightness as seen from Earth
    - b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    + c) an annual change in angular position of a star as seen from Earth
    - d) an astronomical object with known luminosity.
    - e) the total amount of energy emitted per unit time.
2. Luminosity is
    - a) an annual change in angular position of a star as seen from Earth
    - b) a numerical measure of brightness as seen from Earth
    - c) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    - d) an astronomical object with known luminosity.
    + e) the total amount of energy emitted per unit time.
3. A standard candle is
    - a) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    - b) a numerical measure of brightness as seen from Earth
    + c) an astronomical object with known luminosity.
    - d) an annual change in angular position of a star as seen from Earth
    - e) the total amount of energy emitted per unit time.
4. Absolute magnitude is
    - a) a numerical measure of brightness as seen from Earth
    - b) the total amount of energy emitted per unit time.
    - c) an annual change in angular position of a star as seen from Earth
    - d) an astronomical object with known luminosity.
    + e) a numerical measure of brightness as seen from a distance of approximately 33 light-years
5. Relative magnitude is
    + a) a numerical measure of brightness as seen from Earth
    - b) a numerical measure of brightness as seen from a distance of approximately 33 light-years
    - c) an astronomical object with known luminosity.
    - d) an annual change in angular position of a star as seen from Earth
    - e) the total amount of energy emitted per unit time.
6. In 1989 the satellite Hipparcos was launched primarily for obtaining parallaxes and proper motions allowing measurements of stellar parallax for stars up to about 500 parsecs away, which is about ____ times the diameter of the Milky Way Galaxy.
    - a) 15
    - b) 1.5
    - c) 150
    + d) .015
    - e) 0.15
7. An object emits thermal (blackbody) radiation with a peak wavelength of 250nm. How does its temperature compare with the Sun?
    - a) 5 times colder than the Sun
    - b) 2 times colder than the Sun
    - c) 5 times hotter than the Sun
    - d) The temperature is the same
    + e) 2 times hotter than the Sun
8. The "normalized intensity" of a Sun-like star situated one parsec from Earth would be 4πI = 1. What is 4πI for a star with 100 times the Sun's energy output that is situated 10pc from Earth?
    - a) 10$^{-2}$
    - b) 10$^{-3}$
    - c) 10$^{-1}$
    + d) 1
    - e) 10$^{-4}$
9. An orbiting satellite makes a circular orbit 5 AU from the Sun. It measures a parallax angle of 0.2 of an arcsecond (each way from the average position). What is the star's distance?
    + a) 25 parsecs
    - b) 5 parsecs
    - c) 50 parsecs
    - d) 1 parsec
    - e) 10 parsecs
10. A star that is increasing it's temperature while maintaining constant luminosity is
    + a) getting smaller in size
    - b) on the verge of becoming a supernovae
    - c)e) getting larger in size
    - d) in the process of dying
    - e) turning red
11. The range of wavelength for visible light is between
    - a) 5000 and 6000 nanometers
    - b) 1 and 10 nanometers
    - c) 600 and 1200 nanometers
    + d) 400 and 700 nanometers
    - e) 0.1 and 10 nanometers
12. Based on the HR diagrams and images in stars shown in the materials, a very large red supergiant has a diameter that is about ____ greater than a small white dwarf.
    - a) 3x10$^7$
    - b) 3x10$^9$
    + c) 3x10$^5$
    - d) 3x10$^{11}$
    - e) 3x10$^3$

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