there r holes in that. how do we determine the size of these holes?
2007-06-06 04:56:46 · 4 answers · asked by kandee 2 in Science & Mathematics ➔ Engineering
The holes are sized such that their diameter is just smaller than the wavelenght of the microwave rays. Thus the microwaves cant completely enter the hole, whatever their direction might be. Dear kandee pls vote my answer as the best answer.
2007-06-07 06:00:57 · answer #1 · answered by ANKIT SACHDEVA 1 · 0⤊ 1⤋
When any electromagnetic wave reflects from a conducting surface that has small holes in it, there is an evanescent wave extending into and somewhat beyond each hole. It's as though the wave is trying to figure out whether or not it can pass through the opening and so it tries to do that. Even when it discovers that the hole is far too small for it pass through (i.e., much smaller than its wavelength), it still offers electromagnetic intensity in the region just beyond the hole. The extent of the evanescent wave increases with the size of the hole. The microwave oven's screen has very small holes and it is located inside the glass window. The evanescent waves associated with those holes cut off so quickly that you can hold your hand against the glass and not expose your skin to significant microwaves.
2007-06-06 06:06:16 · answer #2 · answered by gatorbait 7 · 0⤊ 0⤋
The waves are about 13.5 cm. So the holes have to be about 10 times smaller to stop the waving to cook our brain when we look into...
2007-06-06 05:12:41 · answer #3 · answered by Scanie 5 · 1⤊ 0⤋
Some simple calculations and then a few tests to make sure it's a good shield.
2007-06-06 05:05:22 · answer #4 · answered by Gene 7 · 0⤊ 0⤋