A convex mirror of focal length f forms an image which is 1/n times the object. The distance of the object from the mirror is :
Answer & explanation
Correct answer: option 1
$ m = \frac{1}{n} = -\frac{v}{-u}$
$ v = \frac{u}{n}$
Mirror Equation
$\frac{1}{v} + \frac{1}{u} = \frac{1}{f}$
$ \frac{n}{u} + \frac{1}{-u} = \frac{1}{f}$
$\Rightarrow u = (n - 1)f$