Question

Define power of a lens. What is its unit? One student uses a lens of focal length 50 cm another of -50 cm. What is the nature lens and its power used by each of them?​

Answer 1

Power of lens is also known as the inverse of the focal length of the lens measured in metre.

$si \: unit \: of \: power \: = dioptre \: \: (d)power \: of \: lense \: = \frac{1}{focal \: length \: in \: metre}$

Unit is an individual thing or person regarded as single and complete but which can also form and individual component of a larger or more Complex whole.

Question: One student uses a lens of focal length 15 cm and another of - 50 cm. What is the nature of the lens and its power used by each of them?

Solution:

$f \: = 50cm \: = 0.5 \: m \:$

$p \: = \frac{1}{f} = \frac{1}{0.5} = 2d$

$for \: convex \: lense \:f \: > 0 = p > 0$

$for \: concave \: lense \: f \: < 0 = p \: < 0$

Lens is convex in the first case and concave in the second case. Power = 2 dioptre in the first case and dioptre in the second case.

Answer 2

Answer:

Explanation:

Lens is convex in the first case and concave in the second case. Power = 2 dioptre in the first case and dioptre in the second case.