If x and y be the distances of the object and image formed by a concave mirror from its focus and f be the focal length then
Answer & explanation
Correct answer: option 2
According to Newton's formula $xy = f^2$.
Note that $m=\frac{f}{f-u}=\frac{f-v}{f}$
or $\frac{f}{x}=\frac{y}{x}⇒xy=f^2$