Question

Three students measured the focal length of a convex lens using parallel rays
from a distant object. All of them measured the distance between the lens and the
inverted image on the screen.

Student A saw a sharp image on the screen and labelled the distance as f1.
Student B saw a slightly larger blurred image on the screen and labelled the
distance as f2.

Student C saw a slightly smaller blurred image on the screen and labelled the
distance as f3.

The relation between the three measurements would most likely be

(a) f1 = f2 = f3.
(b) f1 < f2 and f3.
(c) f3 < f1 < f2.
(d) f1 < f2 and f1= f3.

Answer 1

B is the correct answer