Question

the optical power radiated into unit solid angle per unit emitted surface is called​

Answer 1

Answer:

The power per unit area per unit solid angle is sometimes called sterance. In the radiant case it is measured in watts/m2 steradian and is also called radiance. In the luminous case it is measured in lumens/m2 steradian which is equivalent to candela/m2 = nit. This quantity is also called luminance.