Q.

The electric field in a plane electromagnetic wave is given by : 

Ey=69sin [0.6×103x-1.8×1011t]V/m

The expression for magnetic field associated with this electromagnetic wave is ________ T.       [2026]

1 Bz=2.3×10-7sin [0.6×103x+1.8×1011t]  
2 Bz=2.3×10-7sin [0.6×103x-1.8×1011t]  
3 By=69sin [0.6×103x+1.8×1011t]  
4 By=2.3×10-7sin [0.6×103x-1.8×1011t]  

Ans.

(2)

B^=c^×E^

  c^=i^  because phase of electric field is function of x.

  E^=j^  (given)

  B^=i^×j^=k^

|B|=|E|c=69×0.6×1031.8×1011=693×108

|B|=2.9×10-7

B2=2.9×10-7sin(0.6×103x-1.8×1011t)

(phase is same as that of electric field)