NEET2019PhysicsMagnetic Properties of MatterActual
The electric field of a plane electromagnetic wave of amplitude 2 ~V ~m ⁻¹ varies with time and propagates along z -axis. The average energy density of the magnetic field (in J m ⁻³ ) is
Options
- A13.29 10⁻¹²
- B8.86 10⁻¹²
- C17.72 10⁻¹²
- D4.43 10⁻¹²
Correct answer
B. 8.86 10⁻¹²
Step-by-step solution
Average energy density of the magnetic field is aligned & u_B= 1 4 B₀^2 ₀ ( B₀= E₀ c ) & = 1 4 ₀ E₀^2 ( c= 1 ₀ ₀ ) & = 1 4 8.854 10⁻¹² (2)^2 & =8.854 10⁻¹² ~J ~m ⁻³ 8.86 10⁻¹² ~J ~m ⁻³ aligned