Question

The total solid angle subtended by the sphere is

• A. $0.25\pi$
• B. $0.5\pi$
• C. $4\pi$
• D. $2\pi$
• E. $1\pi$

Answer 1

Answer: (C)

$4\pi$

Solid angle is given by area subtended divided by $r^2$.

$\Omega =\frac{\Delta S}{r^2}$

Now, area subtended by a sphere is the whole surface area of sphere=$4\pi r^2$

$⟹\Omega =\frac{4\pi r^2}{r^2}$

$⟹\Omega =4\pi$

Answer-(E)