I've just rented a house that came with an equipped kitchen, and I've found that the microwave has a rather weird behavior - opening the doors seems to trigger it to start working, which the owners claim "has always been like that". Yet, I've been placing anything I want to heat as fast as possible and without completely opening the door for fear of exposure to microwaves - and I'm curious, assuming there is something wrong with the device, how dangerous is this type of short exposure?
It is dangerous to humans because it heats up things that contain water. You contain water. Some parts of you can't deal with this added heat (your eyes) and will be damaged first.
It also fries sensitive electronics like the embedded radio chips in your phone and laptop when they are close enough. (meters away, not centimeters)
Also, there are laws for for the amount of leakage of a microwave, and being on with open door certainly violates this law. Please unplug and don't use it, ask the landlord to replace it.
IF the oven heats with the door open then
THE OVEN IS HORRENDOUSLY LETHALLY DANGEROUS AND
IT MUST NOT BE USED
It is possible that the light and fan operate when the door is open BUT that the oven doesn't. Answers to these four questions will clarify the matter:
Q1. Can you cook/heat with the door closed?
Q2 Can you cook/heat with the door partially open?
Q3 If you open the door, place a cup of cold water in the microwave and then close the door to a slit so it remains open, after 1 minutes, is the water any warmer?
Q4 What brand and model is the oven? |
Your 4 answers are ...?
If the answer to Q2 and/or Q3 is "Yes" then "you have problems".
If the answer to Q1 is "No" then someone has probably rewired the control switches.
If Q1 Q2 Q3 answers are Yes No No then all is well.
If there IS a problem then:
I've been placing anything I want to heat as fast as possible and without completely opening the door
This MAY be more dangerous than opening it more fully.
The partially opened door may form a "slot radiator" and project a semi-focused beam of energy.
This is NOT just an academic possibility - slot radiation from unintended sources is a common problem.
@crasic's initial comment is so lethally misleading that it should be removed. While there is SOME technical merit in the answer it is partially wrong and a user could suffer severe injury or death if believed.
There is no certainty re how much of a load or resonant structure that will be formed with an open door - and a door opened to just enough to allow the cutout to (mal)function could forma slot antenna that could produce a beam of energy. eg
A child standing by the open oven could receive horrific eye and/or head irradiation injuries.
Note: This fault is so unusual and so impossible to occur in a properly constructed over that it sounds as if it is the product of somebody 'tinkering' with the circuitry. The danger is so high that special care is taken (and required by regulations) to ensure that this cannot happen.