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?
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).
5 min
10 min
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50 min