This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Unknown
For near point of 20 cm, a hypermetropic of +4D has to exercise accommodation of - 
Select and explain. 
A. +4.0 D, B. +9.0 D, C. +10.0 D, D. 0 D
B: +9.0 D
Answer: B: +9.0 D 
Explanation: Ans- B +9.0 D A=P-R where P-is the refractive power of the eye when fully accommodated and R-is the accommodative power of the eye at rest. Hypermetropes have their far point behind eye. Hence, R= -4 Applying this to the formula= A= 100/20 - (-4)= 5 + 4 = +9 D.