# Astronomy college course/Introduction to stellar measurements/questions/Supplement

1 Our Sun is an approximate black body with a peak wavelength at approximately 500nm. If λ is the peak wavelength, then the absolute temperature (i.e., Kelvins) is related to λ by λT = k, where k is a constant. An object emits thermal (blackbody) radiation with a peak wavelength of 250nm. How does its temperature compare with the Sun?

 5 times colder than the Sun 2 times colder than the Sun 5 times hotter than the Sun The temperature is the same 2 times hotter than the Sun

2 Our Sun is an approximate black body with a peak wavelength at approximately 500nm. If λ is the peak wavelength, then the absolute temperature (i.e., Kelvins) is related to λ by λT = k, where k is a constant. An object emits thermal (blackbody) radiation with a peak wavelength of 1000nm. How does its temperature compare with the Sun?

 5 times colder than the Sun 2 times colder than the Sun 5 times hotter than the Sun The temperature is the same 2 times hotter than the Sun

3 Our Sun is an approximate black body with a peak wavelength at approximately 500nm. If λ is the peak wavelength, then the absolute temperature (i.e., Kelvins) is related to λ by λT = k, where k is a constant. An object emits thermal (blackbody) radiation with a peak wavelength of 100nm. How does its temperature compare with the Sun?

 5 times colder than the Sun 2 times colder than the Sun 5 times hotter than the Sun The temperature is the same 2 times hotter than the Sun

4 The distance to a star in parsecs is related to a planet's parallax angle, θ, by the formula, d = r/θ, where d is measured in parsecs, r is the radius of the planet's orbit in AU, and θ is the parallax angle in arcseconds. 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?

 25 parsecs 5 parsecs 50 parsecs 1 parsec e) 10 parsecs

5 The distance to a star, d, is related to a planet's parallax angle, θ, by the formula, d = r/θ, where r is the radius of the planet's orbit, and θ is the parallax angle measured in radians. An orbiting satellite makes a circular orbit 5 AU from the Sun. It measures a parallax angle of 1 arcsecond (each way from the average position). What is the star's distance?

 25 parsecs 5 parsecs 50 parsecs 1 parsec 10 parsecs

6 The distance to a star, d, is related to a planet's parallax angle, θ, by the formula, d = r/θ, where r is the radius of the planet's orbit, and θ is the parallax angle measured in radians. An orbiting satellite makes a circular orbit 5 AU from the Sun. It measures a parallax angle of 0.1 arcsecond (each way from the average position). What is the star's distance?

 25 parsecs 5 parsecs 50 parsecs 1 parsec 10 parsecs