Question

A concave lens has a focal length of -31 {cm}. Find the image distance and magnification that results when an object is placed 29 {cm} in front of the lens.

d1= ? cm
m= ?

Answer 1

The value is
`v  =  440 \  cm`

and

`m  =  16`

Step-by-step explanation:

From the question we are told that

The image distance is
`v  =  29 \  cm`

The focal length is
`f =  -31 \  cm`

From the lens equation we have that

`(1)/(f)  =  (1)/(v)  - (1)/(u)`

=>
`(1)/(-31)  =  (1)/(v)  - (1)/(29)`

=>
`v  =  450 \  cm`

Generally the magnification is

`m  =  (v)/(u)`

=>
`m  =  ( 450)/(29)`

=>
`m  =  16`