Exam 30: Changing Electric Fields

A microwave oven operates with sinusoidal microwaves at a frequency of 2400 MHz.The height of the oven cavity is 25 cm and the base measures 30 cm by 30 cm.Assume that microwave energy is generated uniformly on the upper surface of the cavity and propagates directly downward toward the base.The base is lined with a material that completely absorbs microwave energy.The total microwave energy content of the cavity is 0.50 µJ.What is the intensity of the microwave beam? (c = 3.00 × 10⁸ m/s,μ₀ = 4π × 10^-7 T • m/A,ε₀ = 8.85 × 10^-12 C²/N • m²)

Given that the wavelengths of visible light range from 400 nm to 700 nm,what is the highest frequency of visible light? (c = 3.0 × 10⁸ m/s)

An 800-kHz radio signal is detected at a point 4.5 km distant from a transmitter tower.The electric field amplitude of the signal at that point is 0.63 V/m.Assume that the signal power is radiated uniformly in all directions and that radio waves incident upon the ground are completely absorbed.What is the magnetic field amplitude of the signal at that point? (c = 3.0 × 10⁸ m/s,μ₀ = 4π × 10^-7 T • m/A, Ε₀ = 8.85 × 10^-12 C²/N • m²)

A sinusoidal electromagnetic wave in vacuum delivers energy at an average rate of 5.00 µW/m². What are the amplitudes of the electric and magnetic fields of this wave? (c = 3.0 × 10⁸ m/s, μ₀ = 4π × 10^-7 T • m/A,ε₀ = 8.85 × 10^-12 C²/N • m²)

The energy per unit volume in an electromagnetic wave is

A microwave oven operates with sinusoidal microwaves at a frequency of 2400 MHz.The height of the oven cavity is 25 cm and the base measures 30 cm by 30 cm.Assume that microwave energy is generated uniformly on the upper surface of the cavity and propagates directly downward toward the base.The base is lined with a material that completely absorbs microwave energy.The total microwave energy content of the cavity is 0.50 µJ.What is the amplitude of the electric field? (c = 3.00 × 10⁸ m/s, Μ₀ = 4π × 10^-7 T • m/A,ε₀ = 8.85 × 10^-12 C²/N • m²)

The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.939 W/m².The wave is incident upon a rectangular area,1.5 m by 2.0 m,at right angles.How much total electromagnetic energy falls on the area during 1.0 minute? (c = 3.0 × 10⁸ m/s,μ₀ = 4π × 10^-7 T • m/A, Ε₀ = 8.85 × 10^-12 C²/N • m²)

The magnitude of the magnetic field at point P for a certain electromagnetic wave is 2.12 μT.What is the magnitude of the electric field for that wave at P? (c = 3.0 × 10⁸ m/s)

The magnitude of the Poynting vector of a planar electromagnetic wave has an average value of 0.724 W/m².What is the maximum value of the magnetic field in the wave? (c = 3.0 × 10⁸ m/s, Μ₀ = 4π × 10^-7 T • m/A,ε₀ = 8.85 × 10^-12 C²/N • m²)

If the magnetic field of an electromagnetic wave is in the +x-direction and the electric field of the wave is in the +y-direction,the wave is traveling in the