What Is The Relation Between Power And Focal Length? - Fixanswer

The power of

a lens is inversely proportional to its focal length

. Therefore, a short focal length lens has more power, whereas a lens of long focal length has less power. The power of a convex lens (converging lens) is positive as its focal length is positive.

How are power and focal length of a lens related class 10?

The lens having high power or small focal length will have more

converging

power. So, the lens to obtain more convergent light is of focal length 20 cm.

Is power directly proportional to focal length?

Formula of Power

As power of

a lens is inversely proportional to its focal length

, therefore, a lens of short focal length has more power whereas a lens of long focal length has less power. … The power of a concave lens(diverging lens) is negative as its focal length is negative.

What is the power of convex lens of focal length 25 cm?

In this question it is given that the lens is convex, and its focal length is 25 cm. First we will convert the focal length in meters. As it is a convex lens so its power is positive. Thus, the power of the lens is

+4D

.

Is power of lens dimensionless?

Or, D = [M
⁰
L
¹
T
⁰
]
^{– 1}
= [M
⁰
L
^{– 1}
T
⁰
]. Therefore, the power of lens is dimensionally represented as

[M
⁰
L
^{– 1}
T
⁰
]

.

What is relation between focal length and refractive index?

Relationship between the power of a convex lens and the refractive index of a medium. Apparently,

focal length f is inversely proportional to the refractive index of the medium μ

. Since, Optical Power P=1f. This should imply that optical power is directly proportional to the refractive index.

Why power is inverse of focal length?

Power of a lens represents its ability to converge or diverge a beam of light. Smaller the focal length of the lens,

larger is

its bending power. That is why power is expressed as the reciprocal of focal length.

Why is power inversely proportional to focal length?

It is measured as 1/f (in Dioptre), where f is the focal length of the lens in metre.

If the lens has smaller focal length, then it will cause greater bending of light rays about the focus of the lens

, implying that it has greater power. … Hence, power is inversely proportional to the focal length of the lens.

What is meant by refractive index?

Refractive Index (Index of Refraction) is

a value calculated from the ratio of the speed of light in a vacuum to that in a second medium of greater density

. The refractive index variable is most commonly symbolized by the letter n or n’ in descriptive text and mathematical equations.

What do you mean by 1 dioptre?

A dioptre (British spelling) or diopter (American spelling) is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres. (

1 dioptre = 1 m
^{− 1}

.) It is thus a unit of reciprocal length.

What is the power of a lens with focal length of 10cm?

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Is power of convex lens positive?

Additional Information: Power of convex lens

is positive as it converges the light rays incident on it

. Convex lens is also referred to as a converging lens. For mirrors there is a slight difference in the formula of power but the meaning is the same. So the focal length of the concave mirror is negative.

What is the power of lens having focal length of 2m?

Therefore, the correct answer for the given question is option (D). Note: The power of the lens is said to be 1 dioptre if the focal length of the lens is 1metre. That means, if the corrective power of the lens is

+0.5D

, the required lens is a convex lens of focal length +2m.

Is the power of a lens is 2d what is its focal length?

Given, Power of lens = P = . As, power is in negative sign , it means it is a diverging lens or concave lens. Hence, the focal length of the combination will be

50 c m

.