steradianów

Steradian is a unit of solid angle in the International System of Units (SI). It is analogous to the radian, which is the unit of plane angle. The steradian is defined as the solid angle subtended at the center of a sphere by a portion of the surface of the sphere that has an area equal to the square of the sphere's radius.

The steradian is a dimensionless unit, as it is derived from the ratio of two lengths. It is often used in three-dimensional geometry and physics, particularly in the context of spherical coordinates and in the calculation of solid angles.

The steradian is abbreviated as "sr". For example, a full sphere subtends a solid angle of 4π steradians, and a hemisphere subtends a solid angle of 2π steradians. The steradian is used in various fields, including optics, astronomy, and thermodynamics, to quantify the spread of light, radiation, or other forms of energy.