Question

A concave lens of focal length of 15cm at what distance should an object from the lens be placed so that forms an image 10 cm from the lens. Also find the magnification of the lens.

Answer 1

Answer:

5

Explanation:

it is magnification of a lens

Answer 2

$\huge\boxed{\underline{\mathcal{\red{A}\green{N}\pink{S}\orange{W}\blue{E}\pink{R}}}}$

GIVEN :

focal length =f=-15 cm after sign conventions

image distance=V=-10cm

object distance=?

by lens formula:

1/f=1/v-1/u

1/u=1/v-1/f

= -1/10+1/15

= -3+2/30

=-1/30

u=-30cm

Magnification=m=v/u

=-10/-30=1/3=0.33