Exam 31: Electromagnetic Fields and Waves

An 800-kHz radio signal is detected at a point 9.1 km distant from a transmitter tower.The electric field amplitude of the signal at that point is 0.440 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 average total power radiated by the transmitter? (c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7 T ∙ m/A,ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

A laser with a power of 1.0 mW has a beam radius of 1.0 mm.What is the peak value of the electric field in that beam? (c = 3.0 × 10⁸ m/s,μ₀ = 4π × 10^-7 T ∙ m/A, ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

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 magnitude force does the microwave beam exert on the base of the oven? (c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7 T ∙ m/A,ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

Light of intensity I₀ and polarized horizontally passes through three polarizes.The first and third polarizing axes are horizontal,but the second one is oriented 20.0° to the horizontal.In terms of I₀,what is the intensity of the light that passes through the set of polarizers?

The following are positioned in sequence: A source of a beam of natural light of intensity I₀; three ideal polarizers A,B,and C; and an observer.Polarizer axis angles are measured clockwise from the vertical,from the perspective of the observer.The axis angle of polarizer A is set at 0° (vertical),and the axis angle of polarizer C is set at 50°.Polarizer B is set so that the beam intensity is zero at the observer.Which of the following pairs of angles are possible axis angle settings of polarizer B?

If an electromagnetic wave has components E_y = E₀ sin(kx - ωt)and B_z = B₀ sin(kx - ωt),in what direction is it traveling?

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)

A radiometer has two square vanes (1.0 cm by 1.0 cm),attached to a light horizontal cross arm,and pivoted about a vertical axis through the center,as shown in the figure.The center of each vane is 6.0 cm from the axis.One vane is silvered and it reflects all radiant energy incident upon it.The other vane is blackened and it absorbs all incident radiant energy.An electromagnetic wave with an intensity of 0.30 kW/m² is incident normally upon the vanes.What is the radiation pressure on the blackened vane? (c = 3.00 × 10⁸ m/s, μ₀ = 4π × 10^-7 T ∙ m/A,ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

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 × 10⁸ m/s,c = 3.00 × 10⁸ m/s,μ₀ = 4π × 10^-7 T ∙ m/A, ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

The y component of the electric field of an electromagnetic wave traveling in the +x direction through vacuum obeys the equation E_y = (375 N/C)cos[kx - (2.20 × 10¹⁴ rad/s)t].What is the wavelength of this electromagnetic wave? (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)

In an electromagnetic wave,the electric and magnetic fields are oriented such that they are

A capacitor is hooked up to a resistor and an AC voltage source as shown in the figure.The output of the source is given by V(t)= V₀ sin ωt.The plates of the capacitor are disks of radius R.Point P is directly between the two plates,equidistant from them and a distance R/2 from the center axis.At point P

An 800-kHz radio signal is detected at a point 8.5 km distant from a transmitter tower.The electric field amplitude of the signal at that point is 0.90 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 average electromagnetic energy density 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 22.0-kg mirror with a surface area of 1.0 m² and a reflectivity is bombarded by light of average intensity at an angle of to the normal of its surface.If the light has a duration of how much does the velocity of the mirror change during that time? (c = 3.00 × 10⁸ m/s,μ₀ = 4π × 10^-7 T ∙ m/A,ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

Unpolarized light is incident upon two polarization filters that do not have their transmission axes aligned.If of the light passes through this combination of filters,what is the angle between the transmission axes of the filters?

The intensity of solar radiation near the earth is 1.4 kW/m².What force is exerted by solar radiation impinging normally on a 5.0 m² perfectly reflecting panel of an artificial satellite orbiting the earth? (c = 3.00 × 10⁸ m/s,μ₀ = 4π × 10^-7 T ∙ m/A,ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

If the electric field and magnetic field of an electromagnetic wave are given by E = E₀ sin(kx - ωt)and B = B₀ sin(kx - ωt),and if the value of E₀ is 51 µV/m,what is the value of B₀? (c = 3.0 × 10⁸ m/s)

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)

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)