00:01
In this problem, we have been given that there is a concave mirror, and of course the focal length of this concave mirror will be negative.
00:09
So there is an object that's placed at a distance of 11 cm.
00:13
So we take the object distance as negative because it lies to the left of the pole.
00:19
And the mirror has radius of curvature 30 centimeters.
00:24
So we know that since this is a concave mirror, radius of curvature 2 will be negative.
00:28
And focal length here can be computed by just dividing this radius of curvature by 2, and this gets us the focal length as minus 15 centimeters.
00:38
And now we have to figure out the image distance.
00:42
So to compute the image distance, we will use the mirror formula.
00:46
That's 1 by u plus 1 by v is equal to 1 by f, and v here represents the image distance.
00:53
So putting the values here, we get minus 1 by 11 plus 1 by v is equal.
00:58
Equal to minus 1 by 15 and this gives us 1 by v as 1 by 11 minus 1 by 15 so simplifying this gives us 4 by 165 so from here we can figure out the image distance by reciprocating this 4 by 165 and that comes out to be approximately 41 .25 centimeters.
01:24
Also we observed that the image distance here that we figured out is positive.
01:29
That means the image lies to the right of this mirror.
01:34
And now we have to figure out the magnification.
01:36
So magnification is related to the image distance and the object distance using the formula m is equal to minus v by u.
01:43
So we just put the value here minus 41 .25 divided by u which was minus 11.
01:50
So when we divide 41 .25 with 11, we're going to get the magnification here as 3 .75.
01:58
And of course, this has no unit.
02:01
And now we have to figure out whether the image is real or virtual.
02:05
So we can see the magnification is positive, and that's only possible that the image and the objects are along the same orientation.
02:14
That means the image is upright, or we can see it is erect.
02:18
And of course, if the image is erect, then it will be virtual...