An object is gradually moving away from the focal point of a concave mirror along the axis of the mirror.
Question:
An object is gradually moving away from the focal point of a concave mirror along the axis of the mirror. The graphical representation of the magnitude of linear magnification $(m)$ versus distance of the object from the mirror $(x)$ is correctly given by
(Graphs are drawn schematically and are not to scale)
Correct Option: 3
Solution:
(3) Using mirror formula, magnification is given by
$m=\frac{f}{u-f}=\frac{-1}{1-\frac{u}{f}}$
At focus magnification is $\infty$
And at $u=2 f$, magnification is 1 .
Hence graph (4) correctly depicts ' $m$ ' versus distance
of object ' $x$ ' graph.
