A microwave oven is powered by an electron tube called a magnetron, which generates electromagnetic waves of frequency 2.45 GHz. The microwaves enter the oven and are reflected by the walls. The standing wave pattern produced in the oven can cook food unevenly, with hot spots in the food at antinodes and cool spots at nodes, so a turntable is often used to rotate the food and distribute the energy. If a microwave over intended for use with a turntable is instead used with a cooking dish in a fixed position, the antinodes can appear as burn marks on foods such as carrot strips or cheese. The separation distance between the burns is measured to be 6 cm ± 5%. Fron these data, calculate the speed of the microwaves.

A microwave oven is powered by an electron tube called a magnetron, which generates electromagnetic waves of frequency 2.45 GHz. The microwaves enter the oven and are reflected by the walls. The standing wave pattern produced in the oven can cook food unevenly, with hot spots in the food at antinodes and cool spots at nodes, so a turntable is often used to rotate the food and distribute the energy. If a microwave over intended for use with a turntable is instead used with a cooking dish in a fixed position, the antinodes can appear as burn marks on foods such as carrot strips or cheese. The separation distance between the burns is measured to be 6 cm ± 5%. Fron these data, calculate the speed of the microwaves.

Physics for Scientists and Engineers: Foundations and Connections

1st Edition

ISBN:9781133939146

Author:Katz, Debora M.

Publisher:Katz, Debora M.

Chapter34: Maxwell’s Equations And Electromagnetic Waves

Section: Chapter Questions

Problem 36PQ

See similar textbooks

Similar questions

What is the average magnitude of the Poynting vector 5.00 mi from a radio transmitter broadcasting isotropically (equally in all directions) with an average power of 250 kW?
A radio station broadcasts its radio waves with a power of 50,000 W. What would be the intensity of this signal if it is received on a planet orbiting Proxima Centuri, the closest star to our Sun, at 4.243 ly away?
A 150-W lightbulb emits 5% of its energy as electromagnetic radiation. What is the magnitude of the average Poynting vector 10 m from the bulb?
Why is t1 radiation pressure of an electromagnetic wave on a perfectly reflecting surface twice as large as the pressure on a perfectly absorbing surface?
Assume the helium-neon lasers commonly used in student physics laboratories have power outputs of 0.500 mW. (a) If such a laser beam is projected onto a circular spot 1.00 mm in diameter, what Is its Intensity? (b) Find the peak magnetic field strength. (C) Find the peak electric field strength.
A radio station broadcasts at a frequency of 760 kHz. At a receiver some distance from the antenna, the maximum magnetic field of the electromagnetic wave detected is 2.151011T . (a) What is the maximum electric field? (b) What is the wavelength of the electromagnetic wave?
A radio transmitter broadcasts plane electromagnetic waves whose maximum electric field at a particular location is 1.55103V/m . What is the maximum magnitude of the oscillating magnetic field at that location? How does it compare with Earth’s magnetic field?
A small helium-neon laser has a power output of 2.5 mW What is the electromagnetic energy in a 1.0-m length of the beam?
On its highest power setting, a microwave oven increases the temperature of 0.400 kg of spaghetti by 45.0°C in 120 s. (a) What was the rate of energy absorption by the spaghetti, given that its specific heat is 3.76103J/kg.C ? Assume the spaghetti is perfectly absorbing. (b) Find the average intensity of the microwaves, given that they are absorbed over a circular area 20.0 cm in diameter. (C) What is the peak electric field strength of the microwave? (d) What is its peak magnetic field strength?
Suppose a spherical particle of mass m and radius R in space absorbs light of intensity I for time t. (a) How much work does the radiation pressure do to accelerate the particle (mm rest In the given tine It absorbs the light? (b) How much energy canted by the electromagnetic waves is absorbed by the particle over this time based on the radiant energy incident on the particle?
Check Your Understanding The wave equation was obtained by (1) finding the E field produced by the changing B field. (2) finding the B field produced by the changing E field, and combining the two results. Which of Maxwell’s equations was the basis of step (1) and which of step (2)?
A parallel-plate capacitor has a plate area of A=0.250m2 and a separation of 0.0100 in. What must be must be the angular frequency w for a voltage V(t)=V0sint with V0=100V to produce a maximum displacement displacement current of 1.00 A between the plates?