Question

an object of height 2cm is at a distance of 15cm infront of a concave lens of power -10D find the image size​

Answer 1

Answer:

img size(Ho) = 5 cm

Explanation:

Power of lens(D) = 1/focal length(m)

thus f = 1/-10 = - 0.1 m = - 10 cm

Lens Formula

1/f = 1/v - 1/u

thus 1/v = 1/-10 + 1/-15

= (-3-2)/15 = -6 cm

Hi / Ho = v / u

Ho = Hi * u / v

= 2 * (-15)/(-6)

= 5 cm