A point source of electromagnetic radiation has average power output of 800 watt, then find
(a) Maximum value of electric field at a distance 3.5 m from the source
(b) Maximum value of magnetic field
(c) Average energy density at 3.5 m from the source.

Explanation

`I = (P) /( 4 pir^2) = (800)/(4 xx 3.14 xx (3.5)^2)`
`I =5.2 ("watt")/(m^2)`
(a) `I = (1)/(2) epsilon_(0) E_(0) ^(2)xxc `
`E_(0) = sqrt((2x x I)/(epsilon_(0) xx c )) = sqrt((2xx 5.2)/(8.85 xx 10^(-12) xx 3 xx 10^(8) ))= 0.626 xx 10^(2) = 62.6 (N)/( C)` (c ) `U =(1)/(2) epsilon_(0) E_(0)^(2) = (8.85 xx 10^(-8) )/(2) xx (62.6 )^(2) = 1.74 xx 10^(-8) (J)/(m^3)`