Question

if the power of lens is 2D then what is its focal length​

Answer 1

Answer:-

f = 50 cm

Given :-

Power of lens is = 2 D

To find :-

It's focal length.

Solution:-

Focal length → The distance between the optical center and focus of the lens is known as focal length.

Power :- The degree of convergence and divergence of a mirror is known as its focal length.

The relationship between power and focal length of mirror:-

$\huge \boxed{P = \dfrac{100}{f}}$

Put the given value,

→$2 = \dfrac{100}{f}$

→$2f = 100$

→$f = \dfrac{100}{2}$

→$f = 50 cm$

hence,

The focal length of the lens will be 50 cm.

Answer 2

hello there

Explanation:

Question: if the power of lens is 2D then what is its focal length?

To find: Focal Length of the Lens.

Solution:

Given:

Power of the Lens ( P ) = 2 D

Since,

The Lens is biconvex Lens So, its focal length( f ) will be :

$= > f = \frac{1}{P}$

Here, we are provided that :

Power of the Lens is = 2 D

So, putting the value of Power in the formulae:

■ f = 1/2D

■ f = 0.5 m

Also , we know that:

1m = 100cm

So, 0.5 m = 100 × 0.5 = 50 cm

Focal length = 5 cm [ Answer]

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◍Extra Information:

✪ Focal length: The distance of the principal focus from the pole of the mirror is called the 'focal length' of the mirror.

$= > f = \frac{R}{2}$

Where R = Radius of curvature

■ Focal length of a convex lens is positive while that of concave lens is negative.

✪ Power: The power ( P ) of a thin lens is equal to the reciprocal of its focal length ( f ).

■ The S.I. unit of Power of Lens 'dioptre' .

[ NOTE: The power of a lens of focal length 1metre is 1 dioptre ( 1D) ]

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Hope it helps

Thank you!