Saved Bookmarks
| 1. |
Two thin lenses of power +5D and –2.5D are in contact. What is the focal length of the combination? |
|
Answer» Net power, P = P1 + P2 = + 5 - 2.5 = +2.5D ∴ Focal length, F = 1/P = 1/2.5m = 0.4m =40cm |
|