Question

The angle subtended at the center of a sphere
by its surface area is equal to:
4
A. 3 radian
4
T
B. 3 steradian
C. 4n steradian
D. 2nt steradian​

Answer 1

Answer:

sr is the unit, steradian. Because the surface area A of a sphere is 4πr2, the definition implies that a sphere subtends 4π steradians (≈ 12.56637 sr) at its center. By the same argument, the maximum solid angle that can be subtended at any point is 4π sr.