Metal utensils can indeed heat up faster in a microwave oven compared to plastic or glass utensils. This is because metal is a good conductor of electricity and microwaves work by generating electromagnetic waves that excite water molecules and other electrically polar molecules in food, causing them to heat up. When metal utensils are placed in a microwave, the microwaves induce an electric current in the metal, resulting in the rapid heating of the utensil.
Plastic and glass, on the other hand, are generally considered microwave-safe materials because they do not readily conduct electricity. While they can still heat up to some extent when exposed to microwaves, they are not as efficient at absorbing and conducting the energy, so they tend to heat up more slowly than metal.
It's important to note that using metal utensils in a microwave oven is generally not recommended. The intense heating of metal objects can cause sparks, electrical arcing, and even damage to the oven. It's safer to use microwave-safe materials like glass or microwave-safe plastics that are specifically designed to withstand the heating and cooking process in a microwave oven.