Frequency of Plane Wave with Magnetic Field Expression in Time Domain

[magnifik]

The magnetic field expression for an electric field of a plane wave in air in the time domain is H(t) = y3sin(ωt + 3x + 4z). Find the frequency of the wave.

i am having trouble where to begin on this problem. i know how to solve if there is only 1 direction variable (i.e. just x or just z), but since there is an x and z inside the sin, I'm not sure what to do

 

[tiny-tim]

hi magnifik!

just change the variables … put k = 3x/5 + 4z/5 and see what happens

(doing it in your head should be enough )

 

[magnifik]

hi magnifik!

just change the variables … put k = 3x/5 + 4z/5 and see what happens

(doing it in your head should be enough )

is there a reason you chose the denominator as 5?

 

[tiny-tim]

is there a reason you chose the denominator as 5?

yes!

and what is it? ​

 

[magnifik]

oh i get it. k = sqrt(3^2 + 4^2) = 5

when i find E in phasor form from the given H, how do i know what direction it should be?

 

[tiny-tim]

(just got up :zzz:)

when i find E in phasor form from the given H, how do i know what direction it should be?

i'm confused …

doesn't it depend on the direction of polarisation? ​