Question

A lens has a focal length of 0.1 m .Find the image distance when the object distance is

•A) 0.5 m
•B) 0.08 m
And write the type of the image

Answer 1

A) 0.125 m (the image is real)

B) -0.4 m (the image is virtual)

Step-by-step explanation:

For both situations we will use the Lens Equation:

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

Where:

`f=0.1 m` is the focal length

`u` is the distance between the object and the lens

`v` is the distance between the image and the lens

Isolating
`v`:

`v=(uf)/(u-f)}` (2)

Knowing this, let's begin with the answers:

A) When
`u=0.5 m`

`v=((0.5 m)(0.1 m))/(0.5 m-0.1 m)}`

`v=0.125 m` The image is real

B) When
`u=0.08 m`

`v=((0.08 m)(0.1 m))/(0.08 m-0.1 m)}`

`v=-0.4 m` The negative sign indicates the image is virtual