The electric field part of an electromagnetic wave in vacuum is
`E=3.1(N)/(C)cos[(1.8("rad")/("m"))y+(5.4xx10^(8)("rad")/(s))t]hati`
The wavelength of this part of electromagnetic wave is

Options

A. 1.5m
B. 2m
C. 2.5m
D. 3.5m

Answer

D

Explanation

Given ` E = 3.1 N C^(-1)` `cos [( 1.8 rad m^(-1)) y + (5.4 xx 10^(8) rad s^(-1))t] hati " "….(i)`
Comparing (i) with the equation
`E= E_(0) cos (ky + omega t)" "…….(ii)`
We get, ` k = 1.8 rad m^(-1)`
`E_(0) 3.1 N C^(-1) , c = 3 xx 10^(8) ms^(-1) , omega = 5.4 xx 108 rad s^(-1)`
Now ` lambda = (2pi)/(k) = ( 2 xx 22)/(1.8 xx 7) = 3.5m`