You are given the following three lenses. Which two lenses will you use as an eyepiece and as an objective to construct an astronomical telescope ? Give reason.
| Lenses | Power(D) | Aperture (cm) | | L1 | 3 | 8 | | L2 | 6 | 1 | | L3 | 10 | 1 |
L1 is used as objective because it has largest focal length and largest aperture and L3 as eyepiece as it has a smallest focal length.
