JEE Main20203 Sep 2020Evening ShiftPhysicsElectromagnetic WavesActual
The electric field of a plane electromagnetic wave propagating along the x direction in vacuum is E → = E 0 jcos ( ω t - kx ) . The magnetic field B → , at the moment t = 0 is:
Options
- AB → = E 0 μ 0 ϵ 0 cos ( k x ) k ^
- BB → = E 0 μ 0 ϵ 0 cos ( kx ) j ^
- CB → = E 0 μ 0 ε 0 cos ( k x ) k ^
- DB → = E 0 μ 0 ϵ 0 cos ( k x ) j ^
Correct answer
C. B → = E 0 μ 0 ε 0 cos ( k x ) k ^
Step-by-step solution
B 0 = E 0 C = E 0 1 / μ 0 ε 0 = E 0 μ 0 ε 0 As the light is propagating in x direction and E ^ × B ^   | |   C ^ ∴ B → should be in K ^ direction