00:03
In this problem, we have a projector that has a lens with this focal lens, and we want to use it to project the image of this object here.
00:17
There is a slide with these dimensions.
00:21
On a screen that is located five mirrors from the lens.
00:26
In order to compute the size of the final image, there is the size of the screen that we need, we need the magnification.
00:39
And to get this magnification, we need the object distance that we call it p.
00:48
So let's start with this, computing the value of p.
00:52
For that, we use the lens equation.
00:56
There is this equation here.
01:06
And the focal length we know that is 0 .12 the object distance is what we want to compute and the image distance is 5 meters so this is 1 over 5 from this we can compute the value of p so p is just 0 .1 to 3 meters so let me correct here.
01:45
Okay.
01:49
Now that we have p, we can compute the magnification.
01:55
The magnification is just minus q over p.
02:02
So this is minus 5 over p, there is 0 .123...