Question

focal length of convex lens is 30 cm and size of the image is one quarter of the object calculate the distance of object from lens​

Answer 1

Since image is one quarter from a convex lens

Magnification= -1/4

Let distance of object be 'u' and image formed be 'v'

m=v/u

-1/4=u/v

v= -4u

Now by lens formula

1/f=1/v-1/u

1/30=1/-4u -1/u

1/30=1/ -5u

5u = -30

u = -6cm