Question

The intensity at a distance of 6 m from a source that is radiating equally in all directions is 6.0\times 10^{-10} W/m^2. What is the power emitted by the source

Answer 1

Answer:

P = 271 nW

Explanation:

• If the source is radiating equally in all directions, it can be treated as a point source, so all points located at the same distance of the source, have the same intensity I, which is related to the power by the following expression:

       $I = \frac{P}{A} =\frac{P}{4*\pi *r^{2} } (1)$

• Solving for P, we get:

       $P = I*4*\pi *r^{2} = 6.0e-10 W/m2 * 4 * \pi *(6m)^{2} =271 nW (2)$