A thin lens is placed 50cm from an illustrated object. The image produced has linear…

A thin lens is placed 50cm from an illustrated object. The image produced has linear magnification of (frac{1}{4}). Calculate the power of the lens in dioptres
  • A.
    2.5D
  • B.
    5.0D
  • C.
    10.0D
  • D.
    25.0D
Correct Answer: Option C
Explanation

(frac{1}{v} = frac{1}{u})
m = (frac{v}{u} = frac{1}{4} = frac{v}{50})
v = 12.5
But (frac{1}{v} + frac{i}{u} = frac{1}{f})
= (frac{1}{50} + frac{1}{12.5} = f)
f = 10m
P = (frac{100}{10} = 10D)

You May Also Like