Science

A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?

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Given,

P = +1.5 D

f = ?

We know,

Power of lens (P) = $\dfrac{1}{\text{focal length}}$

As the given power is positive hence, we can say that the lens used is convex (converging) in nature.

Substituting the value of power in formula we get,

+1.5 = $\dfrac{1}{\text{f}}$

f = $\dfrac{1}{\text{1.5}}$

f = 0.67 m

Therefore, focal length is 0.66 m and it is a converging lens.

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