C-09-Q098mediumsingle_mcq
To find the focal length of a convex lens, light from a distant object is focused on a wall. The focal length equals —
To find the focal length of a convex lens, light from a distant object is focused on a wall. The focal length equals —
- athe distance from the object to the lens
- bthe distance from the lens to the wall when the image is sharp
- chalf the distance from object to wall
- dtwice the distance from lens to wall