The electric field of an electromagnetic wave in vacuum is given by the equation E_x = 30 (ky - t) V/m . The average intensity of the electromagnetic wave is nearly: (Take c = 3 10^8 m/s and ₀ = 8.85 10⁻¹² C ^2/ N m ^2 )

Step-by-step solution

From the given equation, the amplitude of the electric field is E₀ = 30 V/m . The average intensity of an electromagnetic wave is given by the formula: I = 1 2 c ₀ E₀^2 Substituting the standard values: I = 1 2 (3 10^8) (8.85 10⁻¹²) (30)^2 I = 1.5 10^8 8.85 10⁻¹² 900 I = 1350 8.85 10⁻⁴ I = 1.19475 W/m ^2 1.2 W/m ^2 Note: Forgetting the factor of 1 2 leads to the peak intensity ( 2.4 W/m ^2 ), which is a common error. Answer: 1.2 W/m ^2