The intensity of an electromagnetic wave is 8 × 10⁷ W/m². What is the amplitude of the magnetic field of this wave? A)8.2 × 10^-4 T B)3.3 × 10^-7 T C)10 T D)14 T E)5.8 × 10^-4 T

Question

Quizplus · Accepted Answer

The intensity of an electromagnetic wave is given by:$$I = \frac{1}{2} c \epsilon_0 E_0^2 = \frac{1}{2} c \mu_0 H_0^2$$where:* I is the intensity in W/m^2* c is the speed of light in m/s* \epsilon_0 is the permittivity of free space in F/m* E_0 is the amplitude of the electric field in V/m* \mu_0 is the permeability of free space in H/m* H_0 is the amplitude of the magnetic field in A/mSolving for H_0, we get:$$H_0 = \sqrt{\frac{2I}{\mu_0 c}}$$Plugging in the given values, we get:$$H_0 = \sqrt{\frac{2(8 	imes 10^7 	ext{ W/m}^2)}{4\pi 	imes 10^{-7} 	ext{ H/m} 	imes 3 	imes 10^8 	ext{ m/s}}} = 8.2 	imes 10^{-4} 	ext{ T}$$Therefore, the correct answer is A.

The Intensity of an Electromagnetic Wave Is 8 × 107

The Intensity of an Electromagnetic Wave Is 8 × 10⁷