00:01
There is only one type of mirror that creates a magnified image, an enlarged image.
00:10
And that is a concave or a converging mirror.
00:19
So we know immediately that this is that type of mirror because the person's face is getting enlarged.
00:28
So that is a very big clue.
00:30
The other big clue is that the magnification is a positive quantity.
00:36
A positive m, if we take a look at the mirror equation, that might not give us a whole lot.
00:45
1 over p, the object distance, plus 1 over q, the image distance, equals 1 over f.
00:54
But the magnification, m is minus q over p.
01:01
The fact that that is positive tells us that the image is virtual.
01:14
And because that image is virtual, we know that the face is in between the mirror and the focal length.
01:27
And of course, the radius of curvature, or the center of curvature, is twice out, twice the focal length out from the mirror...