What is the angle subtended by the topmost letter in the Snellen's chart at the Nodal point of the eye when the person seeing it at 6m from the chart?: (A) 5 min, (B) 10 min, (C) 40 min, (D) 50 min
Answer is D. The topmost letter subtends 5 min at Nodal point of the eye when viewed from 60 m.
So the same letter subtends 50 min at Nodal point of the eye when viewed from 6 m (By cross multiplication).