If image obtained from concave mirror of focal length f is `(1/n)^(th)` times of object, then find object distance.

Options

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

Answer

A, C

Explanation

For concave mirror m = `(f)/(f-u)`
`therefore -1/n=(f)/(f-u)`
`(because` Image formed is small,hence real)
`therefore`u-f=nf
`therefore` u= nf+f
`therefore` u = (n+1)f