Question

calculate the solid angle subtended by an actant of a sphere at the centre of the sphere
(A) π/4
(B) π/3
(C) π/2
(D) π
Please explain it​

Answer 1

------------ANSWER HERE-------------

An octant of sphere is each part of sphere divided by a 3-axis cartesian system plane.

Its surface area is S= 81

×4πr 2 = 2πr 2

Solid angle is given by Ω= r 2

so, the answer is 2/π