If a convex lens of focal length 12cm is used to produce a real image four times the size of the object, how far from the lens must the object be placed?

If a convex lens of focal length 12cm is used to produce a real image four times the size of the object, how far from the lens must the object be placed?

Answer Details

Magnifications = V/U = 4 ∴ V = 4U 1/V + 1/U = 1/f1/4u + 1/U = 1/125/4U = 1/12 4U = 12 x 5 = 60 ∴ U = 15 cm