Problema Solution
A lens in a camera has a focal lens, which is important for focusing the lens in the camera. If an object is at a distance D from the lens that has a focal length F, then to be in focus the distance S between the lens and film should satisfy the equation:
1/S= 1/F-1/D
Write the difference 1/F-1/D as one term.
Answer provided by our tutors
Write the difference 1/F-1/D as one term.
Taking LCM of F,D as FD.
(D-F)/FD is corerct answer.