Question

If the power of a convex lens is 2D.Find it's focal length.
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Answer 1

Given:-

• Power of convex lens lens is +2D

To find:-

• Focal length

Solution:-

Power of convex lens lens is +2D, poitive sign indicates it is a convex lens.

$\implies \sf{ Focal \; Length(in \; meter) = \dfrac{1}{Power \; of \; lens}}$

$\implies {\boxed{\sf{\purple{f = \dfrac{1}{D}}}}}$

$\implies \sf{f = \dfrac{1}{2}}$

$\implies \sf{f = 0.5m}$

$\implies {\boxed{\sf{\red{f = 50cm}}}}$

$\rule{200}{2}$

Answer 2

Answer:

The focal length will be equal to 5 m as:

P=1/f

so,P=1/2=0.5 m

Therefore, the focal length of convex lens of power 2D is 0.5 m.

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