Please give a detailed description of plane angle d theta and solid angle d ohm with appropriate figures - Physics - Units And Measurements

Question

Please give a detailed description of plane angle d theta and
solid angle d ohm with appropriate figures

Jyoti Pant · Accepted Answer

Plane Angle is defined as the amount of rotation about the point of
intersection of two lines that is required to make them overlap on
one another It is measured in radian

Solid angle is a cone subtended by a surface on the center of the
sphere of which the surface is a part It is defined by the ratio of
the area of the surface and square of radius It is measured in
steradian

In the diagram the area S
of the sphere subtends a solid angle, Ω = S/r

2

Please give a detailed description of plane angle d theta and solid angle d ohm with appropriate figures.