How come light comes out of the microwave, but the microwaves do not?

Answer 1

The small holes in the door allow light waves to pass through, thus making it possible to see the food cooking inside, because the frequency of light waves is extremely high, which means that their wavelength very small--physically small enough to pass through small holes. On the other hand, microwaves are lower in frequency, thus they have a longer wavelength (at 2450 MHz, about 4 3/4 inches, in fact). Therefore, microwaves are simply too large to pass through the small holes in the door (or for that matter through exhaust vent openings). To the microwaves, these small perforations actually represent a solid metal wall that effectively blocks or reflects the microwaves back in the opposite direction.

Answer 2

That light comes from a normal lightbulb inside the microwave.
Microwaves are invisible. I'm not completely sure why microwaves don't come out, but i know it's one of these reasons.
Microwaves may be completely safe, and the food is designed to be heated by them, or there is a safe layering between you and the box that cancels out the waves.

Answer 3

The frequency of microwave is not high enough, so it can't go out from the holes.

Answer 4

The holes in the metallic grid in the window are much smaller than the wavelength of the r.f. energy so it forms a Faraday screen which blocks most of the energy.

The wavelength of visible light is much smaller than the holes so it passes through.

Answer 5

Actually they do if the seal around the door is even slightly flawed