The magnetic field of an electromagnetic wave has a peak value of 5.0 × 10^-10 T. What is the intensity of the wave? (c = 3.0 x 10⁸ m/s, c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7T ∙ m/A, ε₀ = 8.85 × 10^-12 C²/N ∙ m²) A) 1.0 × 10^-13 W/m² B) 1.5 × 10^-5 W/m² C) 3.0 × 10^-5 W/m² D) 2.0 × 10^-13 W/m² E) 7.5 × 10⁵ W/m²

Question

Quizplus · Accepted Answer

The intensity of an electromagnetic wave is given by I= 1/2ε0cB², where ε0 is the vacuum permittivity. Plugging in the given values, we get:
I= 1/2(8.85 × 10^-12 C^2/N∙m^2)(3.00 × 10^8 m/s)(5.0 × 10^-10 T)^2
I= 2.78 × 10^-5 W/m^2
Simplifying, we get I= 2.78 × 10^-5 × 10^3 W/m^2 = 2.78 × 10^-2 W/m^2
Thus, the answer is C, 3.0 × 10^-5 W/m^2 (closest value).

The Magnetic Field of an Electromagnetic Wave Has a Peak