00:01
In this problem, we want to compute what is the angular size of the moon when we see it from earth.
00:10
So the angular size is this angle here, and this distance, h, is the size of the object.
00:19
The size of the object in this case is the diameter of the moon that has this value here.
00:26
And this distance here is the distance between the earth and the moon that has this value here.
00:31
So in the first case, we want to compute this angular size without a microscope.
00:40
So as these angles are always small, we can approximately compute it as the tangent of the angle.
00:53
So in this case, the tangent is just h over p.
00:59
And using the values that we have for h &p, we just need to replace here.
01:10
Also replace the value of p.
01:16
And this number here is 0 .00904.
01:26
So this is the angular size of the moon without a microscope.
01:31
In the second part of the problem, we are going to use a microscope.
01:37
And a microscope uses two lenses.
01:41
One is called the objective.
01:43
So the objective has this focal length...