A plane electromagnetic wave travelling along the X- direction has a wavelength of 3 mm . The variation in the electric field occurs in the Y- direction with an amplitude `66Vm^(-1)` .The equations for the electric and magnetic fields as a function of x and t are respectively

Options

A. `E_(y)=33cospixx10(t-(x)/(c))`,
`B_(z)=1.1xx10^(-7)cospixx10^(11)(t-(x)/(c))`
B. `E_(y)=11cos2pixx10^(11)(t-(x)/(c))`,
`B_(y)=11xx10^(-7)cos2pixx10^(11)(t-(x)/(c))`
C. `E_(x)=33cospixx10^(11)(t-(x)/(c))`,
`B_(x)=11xx10^(-7)cospixx10^(11)(t-(x)/(c))`
D. `E_(y)=66cos2pixx10^(11)(t-(x)/(c))`,
`B_(z)=2.2xxcos2pixx10^(11)(t-(x)/(c))`

Answer

D

Explanation

The equation of electric field occuring in Y- direction
`E_(y)=66cos2pixx10^(11)(t-(x)/(c))`
Therefore , for the magnetic field in Z - direction `B_(z)=(E_(y))/(c)=((66)/(3xx10^(8)))cos2pixx10^(11)(t-(x)/(c))`
`=22xx10^(-8)cos2pixx10^(11)(t-(x)/(c))`
`=2.2xx10^(-7)cos2pixx10^(11)(t-(x)/(c))`