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Anonymous users2024-01-24Looking out through the anti-theft mirror from the inside, you can see the upright and shrunken image of the visitor. From this, it can be judged that the role of the security door mirror at this time is equivalent to one (B.)concave lens).
C and D can be excluded first. The convex lens can be an upright magnified virtual image or an inverted real image, but it cannot be an upright and reduced image. So choose B
I've done this question, and I promise it's right.
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Anonymous users2024-01-23This is also the effect of the convex mirror!
Whether you change it or not, the seller has the final say, just find a home to buy it.
It is recommended to choose a door mirror with a lid at the back of 200 times made of zinc alloy or copper material, so that it is safer to see the situation outside the door.
There are a total of 4 lenses in the cat's eye; 1 flat lens in the front and back, 2 concave and convex in the middle, facing each other in the front! As for the principle, I don't know much!
There are problems, but the general brand door has high requirements for locks, so there should be no problem.
As far as the whole market is concerned, there are indeed many types of security doors, the price ranges from a few hundred yuan to several thousand yuan, different materials have different prices, and some of the same material also have different prices, some good and bad. The security door can be roughly divided into stainless steel door (stainless steel security door), copper door (copper security door), aluminum alloy door (aluminum alloy security door), iron.