contestada

Suppose the maximum safe intensity of microwaves for human exposure is taken to be 1.00 W/m2 . (a) If a radar unit leaks 10.0 W of microwaves (other than those sent by its antenna) uniformly in all directions, how far away must you be to be exposed to an intensity considered to be safe

Respuesta :

Answer:

We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.

Explanation:

Let suppose that intensity is distributed uniformly in a spherical configuration. By dimensional analysis, we get that intensity is defined by:

[tex]I = \frac{\dot W}{\frac{4\pi}{3}\cdot r^{3}}[/tex] (1)

Where:

[tex]I[/tex] - Intensity, measured in watts per square meter.

[tex]r[/tex] - Radius, measured in meters.

If we know that [tex]\dot W = 10\,W[/tex] and [tex]I = 1\,\frac{W}{m^{2}}[/tex], then the radius is:

[tex]r^{3} = \frac{\dot W}{\frac{4\pi}{3}\cdot I }[/tex]

[tex]r = \sqrt[3]{\frac{3\cdot \dot W}{4\pi\cdot I} }[/tex]

[tex]r = \sqrt[3]{\frac{3\cdot (10\,W)}{4\pi\cdot \left(1\,\frac{W}{m^{2}} \right)} }[/tex]

[tex]r \approx 1.337\,m[/tex]

We must be approximately at least 1.337 meters away to be exposed to an intensity considered to be safe.