Question

a convex lens forms a real image at a distance of 10cm. if the focal length of a lens is 15cm. then find the position of the object. also find the ray diagram

Answer 1

u = 10cm

v = ?

f = 15cm

1/f = 1/v - 1/u

1/15 = 1/10 - 1/u

1/15 - 1/10 = -1/u

2 - 3/30 = - 1/u

-1/30 = -1/u

1/30 = 1/u

=> u = 30cm