No, microwaves cannot harm people when they are turned off or unplugged. Microwaves work by generating electromagnetic radiation at a frequency of around 2.45 gigahertz, which excites water molecules in food, causing them to vibrate and produce heat. When the microwave is turned off or unplugged, it no longer emits this radiation, and there is no energy being produced to cause harm.
The electromagnetic radiation from a microwave is non-ionizing, which means it lacks sufficient energy to remove electrons from atoms or molecules and cause ionization (damage to DNA and cells). This is different from ionizing radiation, such as X-rays or gamma rays, which can be harmful even when the source is turned off due to the potential residual radiation.
It is essential to follow safety guidelines when using a microwave, such as using microwave-safe containers, avoiding using the microwave when empty, and maintaining the microwave in good condition to prevent any potential hazards. However, when the microwave is turned off or unplugged, it does not pose any harm to people.