A convex lens of focal length f forms an image which is 13/ times the size of the object. Then, the distance of object from the lends is

Options

A. 2f
B. f
C. `(2)/(3)f`
D. `(3)/(2)f`

Answer

A

Explanation

Given `f=-f Rightarrow v=(1)/(3)u`
According to the lens formula,
`(1)/(f)=(1)/(v)-(1)/(u)-(1)/(f)=(1)/((-1//2)u)+(1)/(u)-(1)/(f)`
`(-3+1)/(u)-(1)/(f)=-(2)/(u) Rightarrow u=2f`