The faintest stars visible to the naked eye are called:

Two stars situated at distances of $1$ and $10$ light years respectively from the earth appear to possess the same brightness. The ratio of their real brightness is

The flash spectrum confirms a/an:

The hottest planet of the solar system is

The angle of maximum elongation for Venus is $47^\circ$. The distance of Venus from the Sun in $AU$ is .......

The speed of recession of a galaxy is proportional to its distance.