JAMB - Physics (2025 - No. 75)
A short-sighted person's far point is 95cm. The defect can be corrected using
Diverging mirror of focal length 95cm
Plano convex lens of focal length 90cm
Diverging lens of focal length 95cm
Converging lens of focal length 95cm
Giải thích
Short-sightedness (myopia) means distant objects focus in front of the retina, with the far point at 95 cm. A diverging lens (concave) corrects this by creating a virtual image of distant objects (u = ∞) at the far point (v = -95 cm). Using the lens formula: 1/f = 1/v - 1/u = -1/95 - 0, so f = -95 cm (diverging lens with focal length 95 cm).