magnetic door

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I have no context for this question. The only context I have for "magnetic door" is either a magnetic door lock or a magnetic door holder. Can you tell us something about the item you are asking about?
 
They have magnetic pet doors where the pet wears a magnetic sensor collar that opens the door when they get close to the pet door.

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Guessing....

Guessing....

Venturing a guess the question is about magnetic locks used in security. The kind I'd venture to guess we all bet we at one time could open with enough muscle or force and we all thought wrong?:slaphead:
 
strippers&dykes said:
What causes a magnetic door to function?
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The question in your attachment (which I agree is very badly written) is not about magnetic doors. It is about magnetic door holders. I have only seen these in association with a Fire Alarm System, and only in doors within corridors. There may be other applications. What you have is an electromagnet within the wall, and a piece of metal within the door. When you open the door, the electromagnet attracts the metal piece, and thereby holds the door open. If a fire alarm occurs, the current is removed from the electromagnet, and a spring will force the door to close. The purpose is to establish a smoke barrier, and to prevent a draft of air from feeding the fire.
 
I agree - those questions are terrible.

Most tests have a couple of bad questions - but almost every one of those seems to have something wrong with it.

Some people shouldn't write their own tests.
 
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