Chapter Questions
Outline the difference between a star's absolute magnitude and its apparent magnitude, giving definitions where appropriate.
Explain why a star with a larger apparent magnitude is in fact not as bright as a star with a smaller apparent magnitude.
A star has an apparent magnitude of +8.0 when the observer is $20.0 \mathrm{pc}$ away. When the observer is 2.0 pc away from the star, what will the star's apparent magnitude be?
Further to question 3 , calculate the star's absolute magnitude when the observer is $20.0 \mathrm{pc}$ and then calculate the star's absolute magnitude when the observer is $2.0 \mathrm{pc}$ away. Why are the two values equal?
Calculate the brightness ratio of star ' $P$ ' (apparent magnitude +4.5 ) with star ' $Q$ ' (apparent magnitude +7.0 ).
Explain the purpose of obtaining the colour index of a star.
The magnitude of a star measured through a yellow (visual) filter is +12.5 . Given that it is known that this star has a surface temperature of $3500 \mathrm{~K}$, what would the magnitude of the star be when taken through a blue filter?
In point form, list reasons why photoelectric applications have largely replaced photographic methods for measuring and recording starlight.
Outline some applications of photometry.