Question

What is meant by power of a lens? You have 3 lens L. 1 L 2 L 3 of power +10d, +20d ,-10d respt. State the nature and focal length of image of an object placed at 15cm from the lens draw the ray daig. In support of ur ans

Answer 1

Power of a lens can be defined as they reciprocal of its focal length

L1-- +10d= p=1/f 10=1/f = f=1/10 =0.1

L2-- +20d= p=1/f 20=1/f = f=1/20 = 0.2

L3-- -10d= p=1/f -10=1/f = f=1/-10= -0.1