JEE Main20206 Sep 2020Evening ShiftPhysicsElectromagnetic WavesActual
For a plane electromagnetic wave, the magnetic field at a point x and time t is : B → x ,   t = 1 .2 × 10 − 7 sin 0 .5 × 10 3 x + 1 .5 × 10 11 t k ^ T . The instantaneous electric field E → corresponding to B → is :
Options
- AE → x , t = - 36   sin 0 . 5 × 10 3 x + 1 . 5 × 10 11 t j ^   V m
- BE → x , t = 36   sin 1 × 10 3 x + 0 . 5 × 10 11 t j ^   V m
- CE → x , t = 36   sin 0 . 5 × 10 3 x + 1 . 5 × 10 11 t k ^   V m
- DE → x , t = 36 sin 1 × 10 3 x + 15 × 10 11 t i ^   V m
Correct answer
A. E → x , t = - 36   sin 0 . 5 × 10 3 x + 1 . 5 × 10 11 t j ^   V m
Step-by-step solution
E 0 = B 0 × C = 1 . 2 × 10 - 7 × 3 × 10 8 = 36 As the light is propagating in x direction. & E ^ × B ^ | | C ^ ∴ E → should be in j ^ direction. So electric field E → = E 0 sin E → · ( x , t ) = - 36 sin 0 . 5 × 10 3 x + 1 . 5 × 10 11 t j ^ V m