Question

Find the amplitude of electric and magnetic fields in parallel beam of light of intensity `4.0 Wm^(-2)`

Answer 1

The intesity of plane electromagnetic wave is,
`I = (1)/(2)epsi_(0)E_(0)^(2)c`
`:.` Amplitude of electric field, `E_(0) = sqrt((2l)/(epsi_(0)c))`
`= sqrt((2xx4)/(8.86 xx 10^(-12) xx 3 xx 10^(6))) = 54.87 NC^(-1)`
Further, amplitude of manetic filed,
`B_(0) = (E_(0))/(c) = (54.87)/(3.0 xx 10^(6)) T = 1.83 xx 10^(-7) T`