Suppose that the electric field part of an electromagnetic wave in vacuum is `vec(E )={(3.1 N//C)cos [(1.8 rad//m)y+(5.4xx10^(6)rad//s)]}hat(i)`
Write an expression for the magnetic field part of the wave.

Explanation

Equation for magnetic field,
`vec(B)=B_(0)cos (ky + omega t)hat(k)`
`therefore vec(B)=1.033xx10^(-8)cos {(1.8 y+5.4xx10^(8)t)}hat(k) " "` ….(8)
Here if we take direction of `vec(B)` along `hat(k)` then only, direction of `vec(E )xx vec(B)=` direction of `hat(i)xx hat(k)=-hat(j)=` direction of propagation of given electromagnetic wave = direction of - Y axis.