Question

A microwave oven (Figure) uses microwaves with a wavelength of $12.5 cm$ . The front door of the oven is made of glass with a metal grid inside; the gaps in the grid are a few millimetres across. Explain how this design allows us to see the food inside the oven, while the microwaves are not allowed to escape into the kitchen (where they might harm us).

Question Image

A microwave oven has a metal grid in the door to keep microwaves in and let light out

Accepted Answer

To properly design a microwave oven, one must consider not only the magnetron but also the dimensions and resonant properties of the oven cavity. The designer must strive for a uniform energy density within the cavity for uniform cooking of the food and must be sure the cavity presents the proper load to the magnetron.This design allows us to see the food inside the oven, while the microwaves are not allowed to escape into the kitchen (where they might harm us) because the grid spacing is much smaller than the wavelength of the microwaves, so the waves do not pass through. However, the wavelength of light is much smaller, so it can pass through unaffected

David Sang and Graham Jones Solutions for Chapter: Superposition of Waves, Exercise 3: Question

David Sang Physics Solutions for Exercise - David Sang and Graham Jones Solutions for Chapter: Superposition of Waves, Exercise 3: Question

Questions from David Sang and Graham Jones Solutions for Chapter: Superposition of Waves, Exercise 3: Question with Hints & Solutions

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