A thin convex lens has focal length `f_(1)` and a concave lens has focal length `f_(2)`. They are kept in contact. Now, match the following two columns.

Answer

A, B, C

Explanation

`therefore 1/F=1/(f_(1))+1/(f_(2))orP=P_(1)+P_(2)`
`f_(1)and P_(1)` are positive, `f_(2) and P_(2)` are negative.
If `abs(f_(1))gtabs(f_(2))`, powers of system is negative
If `abs(f_(1))ltabs(f_(2))`, powers of system is positive .