Question

The electromagnetic wave that delivers a cellular phone call to a car has a magnetic field with an rms value of 1.9×10⁻¹⁰ T, The wave passes perpendicularly through an open window, the area of which is 0.21 m² . How much energy does this wave carry through the window during a 33-5 phone call? Number Units

Answer 1

The electromagnetic wave carries 1.84 × 10⁻¹⁴ J of energy through the window during a 33.5-minute phone call.

Step-by-step explanation:

To calculate the energy carried by the electromagnetic wave, we can use the formula:

E = B²A/2μ₀,

where E is the energy, B is the rms value of the magnetic field (1.9×10⁻¹⁰ T), A is the area of the window (0.21 m²), and μ₀ is the permeability of free space (4π×10⁻⁷ Tm/A).

Plugging in the values, we get:

E = (1.9×10⁻¹⁰ T)² × (0.21 m²) / (2 × 4π×10⁻⁷ Tm/A) = 1.84 × 10⁻¹⁴ J.

Therefore, the wave carries 1.84 × 10⁻¹⁴ J of energy through the window during a 33.5-minute phone call.