question_answer 64)

                  Calculate the solid angle subtended by the periphery of an area of \[1\,c{{m}^{2}}\] at a point situated symmetrically at a distance of 5 cm from the area.                

Answer:

                  Solid angle \[\text{=}\frac{\text{Area}}{\text{distanc}{{\text{e}}^{\text{2}}}}\text{ = }\frac{\text{1}}{\text{25}}\text{ = 0}\text{.04 steradian}\]