Question

i. What is meant by the power of a lens? What is its SI unit? ii. Find the focal length in cm of a lens of power -2D. Identify the type of this lens in this case.
iii. A converging lens has a focal length of 250 cm. calculate its power and express it according
to sign convention.

Answer 1

Answer:

the power to converge or diverge the Ray's of light si unit dioptre

Explanation:

f = 100/p then f = 100/ -2d = - 50cm an it is concave lens

Answer 2

Answer:

Power......... -3D

physics, power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt, equal to one joule per second. In older works, power is sometimes called activity. Power is a scalar quantity.