Aplane monochromatic radio wave (λ = 0.3 m) travels in vacuum along the positive x-axis, with a time-averaged intensity i = 45 w/m2. suppose at time t = 0, the electric field at the origin is measured to be directed along the positive y-axis with a magnitude equal to its maximum value. what is bz, the magnetic field at the origin, at time t = 1.5 ns?

magnetic field =  - 6.137 × T

Explanation:

given data

radio wave λ = 0.3 m

intensity I = 45 W/m²

time t = 0

time t = 1.5 ns

to find out

What is Bz

solution

we use here equation of intensity of radiation of electric field that is express as

intensity =    .................1

here we know intensity 45 and c is 3 × m/s² and ∈o is 8.85  × C²/N.m² and E will be here

E =     ...............2

E =

E = 184.15

and

E =      .................3

184.15 =    

= 6.137 × T

and in z axis magnetic field will be here as

B =      ..............4

here k =    

k =   = 20.94

and

f =    

f = =        

so here

time t =      

t =   =  

so ω =

ω =

ω = 6.28 ×

so now from equation 4

B =

B =

B =  - 6.137 ×

so magnetic field =  - 6.137 × T