JEE Main20266 April 2026Evening ShiftPhysicsElectromagnetic WavesActual
For an electromagnetic wave propagating through vacuum, k , E and represent propagation vector, electric field and angular frequency, respectively. The magnetic field associated with this wave is represented by :
Options
- AE k
- Bk E
- C( E k )
- D( k E )
Correct answer
B. k E
Step-by-step solution
For an electromagnetic wave, the direction of wave propagation k is along the direction of E B . Since E , B , and k form a mutually perpendicular right-handed system, the direction of the magnetic field is given by B = k E . The magnitudes of the electric and magnetic fields are related by B = E c . Using the relation for the speed of light c = k , we get B = kE . Combining the magnitude and direction gives: B = B B = kE ( k E ) Since k = k k and E = E E , this simplifies to: B = k E Answer: k E