Question

Question #cf067

Answer 1

We know the lens formula as follows

`1/v+1/u=1/f`

where

`u->"object distance"=-ve`

`v->"imsge distance"=+ve`

`m->"magnification"=-1`

`color(red)"since real image is formed"`

`"Now " v/u=m=1=>v=-u=`

`f->"focal length"=f" for convex lens"`

So the above equation becomes

`-1/u-1/u=1/f`

`=>u=-2f`

Hence it is possible when

`color(blue)("object distance"(u) = 2xx"focal length"(f))`