00:01
Let us begin with subpart a.
00:03
Here the image given is inverted.
00:08
Image is inverted.
00:09
So we know that the magnification will be a negative value.
00:14
Here the magnification is given as 4.
00:16
So we have m.
00:17
This is equal to image height divided by object height.
00:22
This is also equals to minus of image distance divided by object distance.
00:28
This is equals to minus 4.
00:31
So we have minus v by u equals minus 4 or v equals u 4 u.
00:39
Let this expression be numbered as 1.
00:42
Now it is given that the distance between object and image is 0 .6 meters.
00:50
So we have v minus u.
00:52
Here v is image distance and u is object distance.
00:55
So v minus u equals 0 .6 meters.
00:58
Now we can substitute expression 1 for v here.
01:03
So 4u minus u equals 0 .6 or from this expression u equals 0 .2 meters.
01:12
So this is the object distance.
01:15
Now let us substitute this in expression 1.
01:18
So v becomes 4 into 0 .2 meters which is equals to 0 .8 meters.
01:26
So we have the object distance as 0 .2 meters and image distance as 0 .8 meters.
01:36
Now we can use the mirror formula to calculate the focal length of the mirror.
01:42
Mirror formula is given by 1 by f equals 1 by u plus 1 by v...