A converging lens of focal length `f_(1)` is placed in front of and coaxially with a convex mirror of focal length `f_(2)`. Their separation is d. A parallel beam of light incident on the lens returns as a parallel beam from the arrangement, Then,

Options

A. The beam diameters of the incident and reflected beams must be the same.
B. `d=f_(1)-2|f_(2)|`
C. `d=f_(1)-|f_(2)|`
D. If the entire arrangement is immersed in water, the conditions, will remain unaltered.

Answer

A, B