Radiation from microwave ovens

In summary, the conversation discusses the topic of microwave radiation escaping when a microwave oven is opened. While it is commonly believed that no radiation escapes due to the walls of the microwave reflecting it, it is possible for a fraction of the radiation to escape through the open door. However, this escape would be minimal and would dissipate quickly due to the speed of light and the reflective properties of the walls. Overall, the analogy to light is often used to explain why no microwave radiation escapes when the door is opened.
  • #1
gudny
3
0
Everybody seems to agree that when a microwave oven is opened, no radiation escapes. On a different thread, somebody said: "Microwave radiation is like light: it absorbs quickly into objects after the source is turned off." This analogy to light is often used to explain why no microwave radiation escapes when the door is opened.
But if I have understood correctly, the walls of the microwave oven almost completely reflect microwave radiation. So the equivalent thing would be would a light source within a room of mirrors. Where the light would of course not be instantly absorbed.
Say that we had an empty oven and we open it, wouldn´t the radiation that had not been absorbed by walls and magnetron escape through the open door?
 
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  • #2
If you turn off a light bulb in a room full of mirrors and open the door a second later, do you still see the light?
 
  • #3
The radiation is absorbed in the realm of a tiny tiny fraction of a second. If you just hit the button to open the door while the microwave is running, the time it takes for the mechanism to actually open the door is long enough for any microwaves to be absorbed by the oven and food. Even empty the oven is not 100% reflective.
 
  • #4
gudny said:
Everybody seems to agree that when a microwave oven is opened, no radiation escapes. On a different thread, somebody said: "Microwave radiation is like light: it absorbs quickly into objects after the source is turned off." This analogy to light is often used to explain why no microwave radiation escapes when the door is opened.
But if I have understood correctly, the walls of the microwave oven almost completely reflect microwave radiation. So the equivalent thing would be would a light source within a room of mirrors. Where the light would of course not be instantly absorbed.
Say that we had an empty oven and we open it, wouldn´t the radiation that had not been absorbed by walls and magnetron escape through the open door?
What is "almost" here? Whatever it is, use that number and calculate how many times it has to reflect to fade into the background. Then, use the speed of light and the size of the microwave to figure out how long it would take. Is it possible to open the door that fast?
 
  • #5
gudny said:
Say that we had an empty oven and we open it, wouldn´t the radiation that had not been absorbed by walls and magnetron escape through the open door?
Sure, but you are grossly underestimating
1] just how fast light and microwaves move, and
2] just how reflective any surface can be

Even if the walls could reflect a thousand times, the radiation would all be dissipated in less than 3/100,000ths of a second.
 
  • #6
Google tells me that even if we assume a 0.5 m wide microwave, and 1 millisecond for time to open door, the microwaves will be reflected 599,585 times.

https://www.google.com/search?&q=c+*0.001s+/+0.5m

Assuming 99.99% reflection that gives:
.9999599585 = 9 x 10-25%

Not a whole lot, even with very generous estimates.
 

1. What is radiation from microwave ovens?

Radiation from microwave ovens refers to the electromagnetic energy that is emitted from the appliance during the cooking process. This energy is in the form of microwaves, which are a type of non-ionizing radiation.

2. Is radiation from microwave ovens harmful?

No, the radiation emitted from microwave ovens is not harmful. Unlike ionizing radiation, which can damage DNA and cause health problems, non-ionizing radiation does not have enough energy to cause harm to human cells.

3. Are there any safety guidelines for using a microwave oven?

Yes, it is important to follow safety guidelines when using a microwave oven. This includes never operating the oven when it is empty, avoiding using metal or foil in the oven, and keeping a safe distance from the oven while it is in use.

4. Can microwave radiation leak from the oven?

Although microwave ovens are designed to contain the radiation within the appliance, there is a small possibility of leakage. However, all microwave ovens sold in the United States must meet strict safety standards and are tested for leakage before being sold.

5. Can standing near a microwave oven while it is in use be harmful?

No, standing near a microwave oven while it is in use is not harmful. The level of radiation exposure is very low and dissipates quickly as you move away from the appliance.

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