Answer:
Step-by-step 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.