Question

define the following term with reference to spherical mirror : pole , centr of curvature radius of curvature and principal axis

Answer 1

In a spherical mirror -

$\sf{ \bold{ Pole \: - }}$

In a spherical mirror , the pole refers to the central point of apparture .

It is also known as the central point of the reflecting surface .

$\sf{ \bold{Centre \: Of \: Curvature \: - }}$

The centre of curvature refers to the centre of the sphere , from which the mirror was cut .

$\sf{ \bold{Radius \: Of \: Curvature \: - }}$

The distance between the centre of curvature and the pole of a spherical mirror is known as the the radius of Curvature

$\sf{ \bold{ Principle \: Axis \: - }}$

Principal axis is an imaginary line passing through the pole and the centre of curvature of a spherical mirror .

________________

Additional information -

$\sf{ \bold{ Object \: Distance \: - }}$

The distance of any object from the pole of a spherical mirror is known as object distance.

$\sf{ \bold{ Image \: Distance \: - }}$

The distance of an image formed by an object from the pole of a spherical mirror is known as image distance .

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Answer 2

$\underline{\underline{\large\mathfrak{Spherical\ Mirror}}}$

Pole :-

• Pole can be defined as the center of the spherical mirror.
• It is expressed using the alphabet "P".
• The principal axis passes through the pole of a spherical mirror.

$\rule{190}2$

Center of curvature :-

• The point in the center of the mirror that passes through the curve of the mirror and has the same tangent and curvature at that point.
• It is the center of the sphere of which the spherical mirror is a part.
• It is denoted using "C" or "2F" (twice of the focus).

$\rule{190}2$

Radius of curvature :-

• It is the linear distance between Pole and the Center of curvature.
• It is denoted as "R".
• It is twice of the focal length and the relation between radius of curvature and focal length is R = 2f.

$\rule{190}2$

Principal axis :-

• The imaginary line passing through the optical center and the center of curvature of a spherical mirror.

$\rule{190}2$

Note :-

◙ R = 2f

◙ C = 2F

Don't get confused for "f/F" being used in both the cases. R ≠ C. Check whether "f" is in upper case or lower case.