Q.

A magnetic field vector in an electromagnetic wave is represented by, B→=B0sin(2πνt-2πxλ)j^. Its associated electric field vector is ______.       [2026]

1 E→=-νλB0sin(2πνt-2πxλ)k^  
2 E→=-νλB0sin(2πνt-2πxλ)i^  
3 E→=νλB0sin(2πνt-2πxλ)k^  
4 E→=νλB0sin(2πνt-2πxλ)i^  

Ans.

(1)

E^×B^=c^

light is moving along +x direction.

B^=j^ and c^=i^

∴ E^=-k^

E0B0=c=νλ

E0=B0×νλ

E→=B0λν·sin(2πνt-2πλx)(-k^)

   =-νλB0sin(2πνt-2πλx)k^