A microwave oven works by emitting electromagnetic waves called microwaves, which cause water molecules in the food to vibrate rapidly. This rapid vibration generates heat, which cooks or reheats the food. Here's a step-by-step explanation of how a microwave works:
Microwave generation: The microwave oven contains a component called a magnetron, which is responsible for generating the microwaves. The magnetron converts electrical energy into electromagnetic waves at a specific frequency of around 2.45 gigahertz.
Microwaves in the cooking chamber: The generated microwaves are directed into the cooking chamber, which is a metal box with a reflective interior. The reflective walls help to bounce the microwaves around the chamber, ensuring even cooking of the food.
Absorption of microwaves: When the microwaves enter the cooking chamber, they interact with the water molecules present in the food. Water is a polar molecule, meaning it has positively and negatively charged ends. The electromagnetic field of the microwaves causes the water molecules to align with the field, and they start oscillating rapidly.
Heat generation: The rapid oscillation of water molecules creates friction and generates heat. This heat is transferred to the surrounding food, cooking it quickly and efficiently.
Safety features: Microwave ovens are designed with safety features, including an interlock switch that prevents the oven from operating when the door is open. This helps to ensure that the microwaves stay contained within the cooking chamber.
Regarding your second question, when you open the microwave door, the microwave emission should stop immediately due to the interlock switch mentioned above. This switch triggers when the door is opened, cutting off power to the magnetron and stopping the generation of microwaves. Therefore, you should not be exposed to microwave radiation when you open the door of a properly functioning microwave oven. However, it's essential to keep the microwave in good condition, and if you suspect any issues with the door or the safety mechanisms, it should be serviced by a professional. Always follow the manufacturer's guidelines for the safe use of microwave ovens.