A plane e.m. wave travelling along the x-direction has a wavelength of 3mm. The variation in the electric field occurs in the y-direction with an amplitude `66Vm^-1`. The equation for the electric and magnetic fields as a function of x and t are respectively

Options

A. `E_(y)= 33cospi xx 10^(11)(t-(x)/(c)), B_(z)= 1.1 xx 10^(-7) cospi xx 10^(11) (t-(x)/(c))`
B. `E_(y)= 11cos2pi xx 10^(11)(t-(x)/(c)), B_(y)= 1.1 xx 10^(-7) cos2pi xx 10^(11) (t-(x)/(c))`
C. `E_(x)=33cospi xx 10^(11)(t-(x)/(c)), B_(x)= 11 xx 10^(-7) cospi xx 10^(11) (t-(x)/(c))`
D. `E_(x)=66cos2pi xx 10^(11)(t-(x)/(c)), B_(z)= 2.2 xx 10^(-7) cos2pi xx 10^(11) (t-(x)/(c))`

Answer

D

Explanation

`lambda= 3 xx 10^(-3) m, E_(y)= 66V//m`
`B_(z)= (E)/(c)= (660)/(3 xx 10^(8)= 2.2 xx 10^(-7)T`
As propagation direction = `vecE xx vec B`
`implies (i)= (hatj) xx (hatk)`