Two thin convex lenses of focal lengths `f_(1)` and `f_(2)` are arranged coaxially with ‘d’ as the reparation between them. The equivalent lens of the combination with focal length ‘F’ to be replaced for the combination is to be placed

Options

A. midway between the lenses
B. between the lenses positions at stance `(dF_(1))/f_(1)` from position of first lens
C. between the lenses positions at distance `(dF_(1))/f_(1)` from position of second lens
D. Between the lenses positions at distance `(dF_(1))/(f_(1) + f_(2))` from position of first lens

Answer

A