Question

On an optical bench a point object is placed at the mark of 10 cm, a convex lens of focal length 15 cm at the mark of 40 cm and a concave lens of focal length 15 cm placed at the mark of 60 cm

Answer 1

a teacher sets up a stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench . he asks one of the student to suggest the