Question Detail
Question
A myopic individual has a far point of 40 cm from their eye. To enable them to see distant objects clearly, what power of corrective lens is needed?
Correct Answer
Option B is the correct answer.
Detailed Explanation
For distant objects, u = ∞. The corrective lens must form a virtual image at the eye's far point, so v = -40 cm. Using the lens formula 1/f = 1/u + 1/v: 1/f = 1/∞ + 1/(-40) = 0 - 1/40. So, f = -40 cm = -0.4 meters. Power = 1/f = 1/(-0.4 m) = -2.5 diopters.
Hint
A myopic eye needs a diverging lens to push the focus back onto the retina. Remember to convert focal length to meters for power calculation.