Comparing Light Collection Between Pupil and Telescope?
You have the idea right! The amount of light collected is indeed proportional to the area of the collecting surface.

Now, if you want to take it a bit further, try to think about the following:


Binoculars have one lens for each eye, does this mean you get twice the amount of light in the end?
Reflecting telescopes almost always have a secondary mirror which results in part of the light being masked and not collected by the primary mirror. Now imagine you have an 8-inch telescope with a 2-inch secondary mirror, can you calculate again the light collection ratio compared to the naked eye?