Suppose the maximum safe average intensity of microwaves for human exposure is taken to be 2.50 W/m2. 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 average intensity considered to be safe

Explanation:

Since the surface area of the sphere of radius 'r' is given by 4πr² the intensity of microwaves at distance 'r' can be determine by using

I(r) = P/S

Where

P is power and it is given as P= 10W

'S is the surface area S=4πr²

I is intensity and it is given as

I = 2.5W/m²

Then,

I = P/S

I = P/4πr²

Ir² = P/4π

r² = P/4Iπ

r = √(P/4Iπ)

r = √(10/4π×2.5)

r = √0.3183

r = 0.564m

You must be 0.564m far away for safety against been exposed to radiation.

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