00:01
For this problem on the topic of image formation, we are told that a concave mirror forms an inverted image four times larger than an object.
00:09
We want to find the focal length of the mirror, assuming we know the distance between the object and the image.
00:14
Secondly, we want to look at a convex mirror that forms a virtual image half the size of the object, and we want to find the radius of coverage of that mirror, assuming again we know the distance between the image and the object.
00:26
So firstly for our concave mirror, we know the magnification is minus 4, and this is negative since the image is inverted.
00:36
We also know the magnification is defined as minus q over p, where q is the image distance and p is the object distance.
00:46
So from here we can see that q is equal to 4 times p.
00:52
So the image distance is 4 times the object distance.
00:55
Now we are also given the fact that the difference between the two q minus p is 0 .6 meters.
01:08
And from above, this can be written as 4p, which is q minus p.
01:16
So we can immediately solve for p and q.
01:20
So we get p to be 0 .2 meters and q to be 0 .8 meters.
01:29
We solve that equation...