00:01
Hello, in the question we have given that a concave mirror has a radius of curvature.
00:06
So we have given the radius of curvature that is equals to 20 centimeters.
00:12
So we know one relation that is f is equals to r by 2.
00:17
So from here, if i plug the value, so this will be 20 by 2.
00:21
So i will get the focal length as equal to 10 centimeters.
00:26
Further, the image formed in mirror is 2 .5 times size of object.
00:36
So how far is the mirror from the object? so we have to find out the object distance.
00:41
So now here the magnification is given.
00:44
Magnification is given that is 2 .5.
00:47
So we know the formula.
00:49
So we have the formula that is magnification.
00:55
So the magnification formula is m is equals to minus v by u.
01:00
So if i plug the values, so this m will be equal to minus v, v, sorry.
01:08
So we have given the magnification itself that is 2 .5 that is equals to minus v by u.
01:15
So which implies that, so which implies that v is equals to minus of 2 .5 u.
01:25
So we will use this relation.
01:28
So this relation let us put over here...