An image of size `(1)/(n)` times that of the object is formed in a convex mirror. If r is the radius of curvanture of the mirror, calculate the object distance.

Explanation

Considering the mod value only, magnification,
`m=(1)/(n)=(v)/(u) or , v =(u)/(n)`
We know, `(1)/(v)+(1)/(u)=(1)/(f) or, (n)/(u)+(1)/(-u)=+(1)/(f)` [Here object distance =-u]
`or, " " (n)/(u)-(1)/(u)=(1)/(f) or ((n-1))/(u)=(1)/(f) or, u = (n-1)f`
`"Again", " " f=(r)/(2), "then" u=(n-1)(r)/(2)`
`therefore "Object distance"= (n-1)(r)/(2).`