Question
Here three lenses have been given. Which two lenses will you use as an eyepiece and as an objective to construct an astronomical telescope?
|
Lenses |
Power (P) |
Aperture (A) |
|
L1 |
3D |
8 cm |
|
L2 |
6D |
1 cm |
|
L3 |
10D |
1 cm |
Solution
For an astronomical telescope, since the aperture of lens L1 is largest, it is used as objective for a telescope. The focal length of lens L3 is smaller and hence cn be used as eyepiece.
