An image of an object obtained by a convex mirror is n times smaller than the object. If the focal length of lens is f, the object distance would be ...........

Options

A. `f/n`
B. `(f)/((n-1))`
C. `(n-1)f`
D. nf

Answer

A, C

Explanation

For convex mirror image is always virtual and magnification m=`v/u`
here, `m=1/n`
`therefore 1/n=v/u`
`therefore v =u/n`
now,`1/f=1/u+1/n`
`therefore1/f =(1)/(-u)+n/u`
`therefore 1/f=(-1+n)/(u)`
`therefore u=(n-1)f`