The intensity of electromagnetic radiation:

$\overline{){\mathbf{I}}{\mathbf{=}}\frac{\mathbf{P}\mathbf{o}\mathbf{w}\mathbf{e}\mathbf{r}\mathbf{,}\mathbf{}\mathbf{P}}{\mathbf{A}\mathbf{r}\mathbf{e}\mathbf{a}\mathbf{,}\mathbf{}\mathbf{A}}}$

In terms of the electric field, the average intensity is equal to:

$\overline{){\mathbf{I}}{\mathbf{=}}\frac{\mathbf{1}}{\mathbf{c}{\mathbf{\mu}}_{\mathbf{0}}}{\mathbf{\xb7}}\frac{{\mathbf{E}}^{\mathbf{2}}}{\mathbf{2}}}$

**(a)**

The area is spherical, A = 4πr^{2}

Power, P = 14.5 W

I = 1.00 W/m^{2}

Suppose the maximum safe average intensity of microwaves for human exposure is 1.00 W/m^{2}. Early radar units leaked radiation more than modern ones do, which caused identifiable health problems, such as cataracts, for people who worked near them.

a) if a radar unit leaks 14.5 W microwave radiation uniformly in all directions, what is the closest distance, in centimeters, you can be to the unit and still be considered safe? Assume that the power spreads uniformly with no complications from absorption or reflection.

b) What is the maximum electric field strength (in volts per meter) of the microwave radiation at the maximum safe intensity?

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