Question

Explain following terms,Pole,Principal axis,Radius of curvature,Focal length

Answer 1

In spherical mirror there is centre of spherical mirror and radius of spherical mirror.

Pole - The centre point on the surface of concave or convex mirror.

Principal axis - The line joining the pole and centre of curvature.

Centre of curvature - The centre of the sphere in which mirror is part.

Radius of curvature- The radius of sphere .

Focal length - The distance between pole and Principal focus is called focal length.

Answer 2

$\huge{\bf{\sf{\underline{\underline {ANSWER:-}}}}}$

$\large\sf{\underline {\star{Pole:-}}}$

The centre point of the reflecting surface of the spherical mirror is called Pole.

➡Refer to attachment 1(Point X and X'are the pole ).

$\large\sf{\underline {\star{Principal\:axis:-}}}$

The line joining pole and centre of curvature extended on both sides is known as Principal axis.

➡Refer to attachment 2(line passing through Point C and point X).

$\large\sf{\underline {\star{Radius\:of\:Curvature:-}}}$

The radius of the hollow sphere of the glass of which the given mirror forms a part is known as Radius of Curvature.

OR

The distance between the centre of curvature and pole of the spherical mirror is termed as Radius of Curavature.

➡Refer to attachment 2(Distance between point C and point X).

$\large\sf{\underline {\star{Focal\:Length:-}}}$

When a beam of light travelling parallel to principal axis, actually meet or appear to meet after reflection or refraction at any point of principal axis, then that particular point is known as Focus Point.

The distance between the pole and focus point is called Focal length.

➡Refer to attachment 3(Distance FP is the focal length. )