Question

A converging lens has the focal length of 25 cm. A 10-cm object is placed at 30 cm in front of the lens. How far is the image from the lens? What is the size of the image?

Answer 1

Step-by-step explanation:

Given that,

Focal length of a converging lens, f = +25 cm

Size of the object, h = 10 cm

Object distance, u = -30 cm

We need to find the image distance and the size of the image.

Using lens formula,
`(1)/(v)-(1)/(u)=(1)/(f)`, v is image distance

`(1)/(v)=(1)/(f)+(1)/(u)\\\\(1)/(v)=(1)/(25)+(1)/((-30))\\\\v=150\ cm`

Magnification,

`m=(v)/(u)=(h')/(h)`

h' is the size of image

`h'=(vh)/(u)\\\\h'=(150* 10)/((-30))\\\\h'=-50\ cm`

So, the image distance is 150 cm the size of image is 50 cm.