STANDARDPhysics-Electromagnetic Waves
STANDARD Physics Energy Density MCQ Question
Type: MCQ-numerical-Medium-Class 12
The rms value of the electric field of the light coming from the sun is 720 N C⁻¹. The average total energy density of the electromagnetic wave is
A
3.3 × 10⁻³ J m⁻³
B
4.58 × 10⁻⁶ J m⁻³
C
6.37 × 10⁻⁹ J m⁻³
D
81.35 × 10⁻¹² J m⁻³
Correct Answer
Option B
Detailed Explanation
Total average energy density of electromagnetic wave is ½ε₀E²ᵣₘₛ = 8.85 × 10⁻¹² × (720)² = 4.58 × 10⁻⁶ J m⁻³.
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