A myopic person has a power of -1.25 Dioptre. What is the focal length and nature of his lens ?
50 cm and convex lens
80 cm and convex lens
50 cm and concave lens
80 cm and concave lens
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-1 – 2016
– Given P = -1.25 D.
– Focal length f = 1 / P = 1 / (-1.25) meters = -0.8 meters.
– Converting to centimeters: -0.8 meters * 100 cm/meter = -80 cm.
– A negative focal length indicates a concave lens. Myopia (nearsightedness) is corrected using concave lenses to diverge light rays before they reach the eye’s lens.