Question

please answer me fast​

Answer 1

Given:-

• Power = 2D

To find:-

• Focal length = ?

Solution:-

We know:

$\leadsto \underline{\boxed{\sf Power=\frac{1}{focal\ length} }}$

Therefore,

$:\implies \sf 2=\frac{1}{f} \\\\:\implies \sf 2f=1\\\\:\implies \sf f=\frac{1}{2} \\\\:\implies \boxed{\boxed{\sf f=0.5m}}$

It is a convex lens.

Hence, the focal length of the lens is 0.5m or 50cm.

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Know more:-

✦Focal length: The distance between the centre and the focal point is known as focal length.

$\leadsto \boxed{\sf f=\frac{-R}{2} }$

Where R = radius of curvature.

✦Lens formula:

$\leadsto \boxed{\sf \frac{1}{v} -\frac{1}{u}=\frac{1}{f} }$

Where,

v = image distance

u = object distance

f = focal length

✦Lens formula is applicable to both convex & concave lenses.

✦Power of lens: Power of lens is the reciprocal of focal length.

SI unit - Dioptre(D)

✦Power of a convex lens is +ve & for concave lens it is -ve.

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Answer 2

Answer:

hlo army hope you are doing well!