David Sang and Graham Jones Solutions for Chapter: Astronomy and Cosmology, Exercise 2: Questions

The radiant flux intensity F of light from a lamp at a distance of $10 \mathrm{cm}$ is $0.32 \mathrm{W}{ \mathrm{m}}^{-2}$. Calculate F from the same lamp at a distance of $15 \mathrm{cm}$. State any assumption(s) you make.

Use data from Table to determine, to two significant figures:

(a) the distance of Sirius from the Earth in metres.

Use data from Table to determine to two significant figures the luminosity (in W) of Canopus.

Use data from Table to determine, to two significant figures the luminosity (in W) of Vega.

Use data from table to determine two significant figures the radiant flux intensity measured at the Earth from Sirius.

Use data from Table to determine, to two significant figures the radiant flux intensity measured at the Earth from  Alpha Centauri.

This question is about Sirius and Arcturus. With the help of calculations and data from Table, show that Sirius is brighter than Arcturus.

The radiant flux intensity from a star measured at the Earth is $2.7\times {10}^{-9} \mathrm{W}{ \mathrm{m}}^{-2}$. The luminosity of the star is $1300L_o$. Calculate the distance of this star from the Earth in metres.