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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