Question

5. 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 dioptre. What is the focal
length of the lens required for correcting (i) distant vision, and (ü) near vision?
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Answer 1

Answer:

For Distant vision : -18.1 cm or - 0.18 m

For near vision :  66.67 cm or 0.66m

Explanation:

For distant vision

1/f = -5.5

f = -0.18m

For near vision

1/f = 1.5

f = 0.66m