Question

practice it!
all of the following are correct, except:
food in a microwave oven gets hot because the electromagnetic energy emitted by the oven makes the molecules speed up and move more.
like conduction and convection, radiation can not occur in an empty space.
radiation is the transfer of thermal energy through electromagnetic waves.
popcorn kernels pop when the molecules inside the kernel move around enough to make it break open.

Explanation:

1. Analyze the first statement: Microwaves use electromagnetic energy to make food molecules vibrate (speed up), generating heat. This is correct.
2. Analyze the second statement: Conduction needs a medium (direct contact), convection needs a fluid medium, but radiation (like light, heat from the sun) can travel through empty space (vacuum) as electromagnetic waves. So the claim that radiation can't occur in empty space is wrong.
3. Analyze the third statement: Radiation is defined as thermal energy transfer via electromagnetic waves (e.g., infrared, visible light). This is correct.
4. Analyze the fourth statement: When popcorn kernels are heated, water inside turns to steam, molecules move more, pressure builds, and the kernel pops. This is correct.

Answer:

The incorrect statement is: Like conduction and convection, radiation can not occur in an empty space.