What is steradian? How can it define mathematically?
Answers
Answer:
A steradian is used to measure "solid angles"
A Radian "cuts out" a length of a circle's circumference equal to the radius. A Steradian "cuts out" an area of a sphere. equal to (radius)2. The SI Unit abbreviation is sr. The name steradian is made up from the Greek stereos for "solid" and radian.
Answer:
Steradian is the unit of solid angle.The steradian is a dimensionless unit
Explanation:
The steradian is the SI unit of solid angle. It is used in three-dimensional geometry, and is analogous to the radian, which quantifies planar angles. Whereas an angle in radians, projected onto a circle, gives a length on the circumference, a solid angle in steradians, projected onto a sphere, gives an area on the surface. The name is derived from the Greek
The solid angle is related to the area it cuts out of a sphere:
Ω = A/r^2 sr
where
Ω is the solid angle
A is the surface area of the spherical cap, A=2*pi*r*h
r is the radius of the sphere, and
sr is the unit, steradian.