Question

If power of lens is 2.0 d then find its focal length in centimetre what should be the nature of lens

Answer 1

Explanation:

Power of lens, P= 1/f

P= -2D

f= -1/2 = -0.5 m

A concave lens has a negative focal length. Hence, it is a concave lens.

Answer 2

Answer:

The lens used is convex in nature.

Explanation:

Power= 1 / focal length

Given,

Power of the lens = +2.0D

because the given power is positive,

Therefore, we are able to say that the lens used is convex in nature.

substituting the value of power in the formula we tend to get,

2 = 1 / focal length

⇒focal length= 1 / 2

⇒focal length=0.5m

⇒focal length=50cm

Therefore, the distance is 50 cm, and also the lens used is convex in nature.

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