Question

At what distance must an object be placed from a convex lens of a focal length 25 cm so as to attain a real image three times the size of the object?

Answer 1

Answer:

Use lenses formula

1/f = 1/v-1/u

1/18=1/24-1/u

U = - 72cm

Magnifications m = v/u =24/(-72)

-. 3

And image formed is inverted -ve sign show that

Answer 2

Answer:

33.3 cm is the correct ans