Microwave doors block radiation using a metal mesh with holes smaller than the wavelength of microwaves, but larger than visible light waves.
The metal mesh in a microwave door acts as a Faraday cage for microwave radiation. Microwaves have a relatively long wavelength, typically around 12 cm. The holes in the mesh are significantly smaller than this wavelength, preventing the microwaves from passing through and escaping the oven. However, visible light has a much shorter wavelength, on the order of nanometers, allowing it to easily pass through the same holes, which is why you can see inside the microwave.
While microwave doors are designed to contain radiation, it's always wise to ensure your appliance is in good condition and not damaged.
How does a microwave leak detector tool work?
A microwave leak detector tool typically measures electromagnetic radiation levels. These devices often contain a sensor that is sensitive to microwave frequencies. You move the detector slowly around the seams and door of the microwave oven while it is operating (usually on a high power setting). If the detector registers radiation levels above a certain threshold, it indicates a potential leak. It's important to follow the manufacturer's instructions for the specific tool, as accuracy can vary, and professional testing is more definitive.