Two thin lenses of focal length `f_(1)` and `f_(2)` are in contact and coaxial. The power of the combination is

Options

A. `(f_(1)+f_(2))/(f_(1)f_(2))`
B. `sqrt(f_(1)/f_(2))`
C. `sqrt(f_(2)/f_(1))`
D. `(f_(1)+f_(2))/2`

Answer

1

Explanation

`1/F = 1/f_(1) + 1/f_(2)`
So. P=`(f_(1)+f_(2))/(f_(1)f_(2))`