Question

If the cornea were simply a thin lens in air, what would be its focal length? Express your answer in millimeters to three significant figures. Measurements on the cornea of a person's eye reveal that the magnitude of the front surface radius of curvature is 7.88 mm, while the magnitude of the rear surface radius of curvature is 7.28 mm (see (Figure 1)), and that the index of refraction of the comea is 1.38 FAXD ? mm Submit Request Answer Figure Part B 1 of 1 If the cornea were simply a thin lens in air, what would be its power in diopters? Express your answer in diopters to three significant figures. Front surface Rear surface Ρ ΑΣΦ ? diopters

Answer 1

A) using sensmaker's equation for a thun lens, = (n-1) f - Ra ²) R ni R nadius where f is the focal length of lens index of refraction of curvature of förest surface (front face) radius of curvature of second surface & rear face) Direction of outgoing light is not same as centre of Ra curvature C. 7 41.38-14 bo R, 7.88 mm Ra 7.28 mm Hence, (1.38 -1) f + L 7.28 7.88

& (0.38) 0.1269 + 0,1373) (0.38) 40,0104) f f = 0.003952 f = 253.16 mm focal lengta 253 mm 0853m B) Power 1 f Power (D) - I focal length - 253 mm O. 253 -0.253 m 3,95 D Power 1 4 Dioptre

Answer 2

incorrect signs, R1 and R2 should both be positive.