Question

b)i)What is meant by power of lens? Write the SI unit.

Answer 1

Answer:

Power of lens is known as the inverse of the focal length of the lens measured in meter(m). S.I unit of power = Dioptre (D) Power of lense = 1/ focal length in meter. The focal length of 1st lense f1 = 40 cm = 0.4 m. The lense used is a convex lens because the focal length is a positive value.

Explanation:

here is your answer

Answer 2

Power of lens is known as the inverse of the focal length of the lens measured in meter(m). 

S.I unit of power = Dioptre (D) 

Power of lense = 1/ focal length in meter.

The focal length of 1st lense f1 = 40 cm = 0.4 m. The lense used is a convex lens because the focal length is a positive value.