A person needs a lens of power -5.5 dioptres for correcting his distant vision. For correcting his near vision, he needs a lens of power +1.5 dioptres. What is the focal length of the lens required for correcting a) Distant vision Near vision
ScienceClass 10ICSEAnswered 27 Mar 2026
Answer
- For distant vision, P = -5.5D
P = 1/f
f = 1/P = -18.18cm
- For near vision, P = 1.5D
P = 1/f
f = 1/P = 66.66cm