JEE Main202431 Jan 2024Morning ShiftPhysicsElectromagnetic WavesActual
In a plane EM wave, the electric field oscillates sinusoidally at a frequency of 5 × 10 10 Hz and an amplitude of 50 V m – 1 . The total average energy density of the electromagnetic field of the wave is : [Use ε 0 = 8 . 85 × 10 – 12 C 2 N - 1 m - 2 ]
Options
- A1 . 106 × 10 – 8 J m – 3
- B4 . 425 × 10 – 8 J m – 3
- C2 . 212 × 10 – 8 J m – 3
- D2 . 212 × 10 – 10 J m – 3
Correct answer
A. 1 . 106 × 10 – 8 J m – 3
Step-by-step solution
Total average energy density of the electromagnetic field is given by, U E = 1 2 ε 0 E 0 2 . ⇒ U E = 1 2 × 8 . 85 × 10 - 12 × 50 2 = 1 . 106 × 10 – 8 J m – 3