JEE Main201912 Apr 2019Evening ShiftPhysicsElectromagnetic WavesActual
A plane electromagnetic wave having a frequency f = 23.9   G H z propagates along the positive z - direction in free space. The peak value of the Electric Field is 60 V / m . Which among the following is the acceptable magnetic field component in the electromagnetic wave?
Options
- AB → = 2 × 10 - 7 sin 0.5 × 10 3 z - 1.5 × 10 11 t i ^
- BB → = 2 × 10 - 7 sin 1.5 × 10 3 x + 0.5 × 10 11 t j ^
- CB → = 2 × 10 7 sin 0.5 × 10 3 z + 1.5 × 10 11 t i ^
- DB → = 60 sin 0.5 × 10 3 x + 1.5 × 10 11 t i ^
Correct answer
A. B → = 2 × 10 - 7 sin 0.5 × 10 3 z - 1.5 × 10 11 t i ^
Step-by-step solution
B = E c = 60 3 × 10 8 = 2 × 10 - 7 The magnetic field can be written as, k = 2 π λ = 2 π c / f ≈ 500 ω = 2 π f ≈ 1.5 × 10 11 B → = 2 × 10 - 7 sin ( 0.5 × 10 3 z - 1.5 × 10 11 t ) i ^