00:01
Hey everyone in this portion we have been given we have been given a concave mirror okay a concave mirror okay and for this concave mirror we have been given the radius of curvature as 40 centimeter okay and it has been said that the size of the image is twice as that of object, means the magnification is minus 2, okay, because as it is a real image, so we have to put the minus sign and we have to tell the value of you, which is the distance of the object from the mirror, okay? so, in order to calculate the value of you, first of all, we have to find out the value of focal length, okay, which is equal to radius of curvature divided by 2.
01:03
Okay, that will become 40 divided by 2.
01:06
That is equal to 20 centimeter.
01:09
Now, we have to use the expression, m is equal to f divided by f minus you.
01:18
Now, we know the value of m, which is minus 2.
01:21
The value of the f is 20.
01:23
Again, the value of the f is 20...