Microwave ovens commonly use electromagnetic radiation oscillating at a frequency of…
PHYSICS · Multi-part · AP · Physics 2: Algebra-based · Waves Sound and Physical Optics · Waves Sound and Physical Optics
Problem
Microwave ovens commonly use electromagnetic radiation oscillating at a frequency of 2.45GHz to heat food. For the purpose of this problem, treat the microwaves as traveling in air at 3.00×108m s−1.
(a) Determine the period of the microwaves.
(b) Calculate the wavelength of the microwaves in air.
(c) In a particular oven cavity, adjacent regions of maximum heating occur where the electric field is at antinode positions. These regions are separated by one-half of a wavelength. If two consecutive antinodes are measured to be 6.12cm apart, evaluate whether this observation is consistent with your result from part (b). Show quantitative support for your conclusion.
(d) A metal rack is inserted that effectively shortens the cavity height, creating standing waves with a different pattern. Qualitatively predict how the positions of the antinodes would change if the effective cavity dimension is reduced, and explain your reasoning in terms of wavelength.