Question

At what distance should an object be placed from a convex lens of focal length 18 cm to obtain an image at
36 cm from it? What will be the magnification produced in this case ?​

Answer 1

Answer:

Focal length,f=18cm

Image distance,v=36cm

Object distance,u=?

As we know that mirror formula is 1/v-1/u=1/f

1/36-1/u=1/18

1/36-1/18=1/u

u=-36cm

as we know that magnification for lenses=m=v/u

m=36/-36

m=-1