In a travelling plane electromagnetic wave, the maximum magnetic field is `1.26 xx 10^(-4)` T . The intensity of the wave is (Assume, `mu_0 = 126 xx 10^(-6) H//m`)

Options

A. `1.56 xx 10^6 (W)/(m^2)`
B. `1.89 xx 10^6 (W)/(m^2)`
C. `8.92 xx10^6 (W)/(m^2)`
D. `4.62 xx 10^6 (W)/(m^2)`

Answer

B

Explanation

Given , maximum magnetic field ,
`B_0 = 1.26 xx 10^(-4) t`
` mu_0 = 1.26 xx 10^(-6) H//m`
` therefore ` Intensity of EMW (Electromagnetic wave) is given by
`I = 1/2 (B_0^2 C)/(mu_0) = 1/2 xx ( (1.26 xx 10^(-4) )^2 xx 3 xx 10^8)/(1.26 xx 10^(-6) ) `
` =1/2 xx (1.26 xx 1.26 xx 10^(-8) xx 3 xx 10^8)/(1.26 xx 10^(-6) )`
` = 0.63 xx 3 xx 10^6 = 1.89 xx 10^6 W//m^2`