A magnifying glass (a positive lens) with a focal length of +6 cm is placed 2 cm above a page of print. What is the magnification of this image?
Magnification=f/f-do
m=6/6-2
m=1.5
To calculate the magnification of an image formed by a lens, you can use the formula:
magnification = - (image distance / object distance)
In this case, the focal length of the lens is given as +6 cm, and the lens is placed 2 cm above the page of print. The object distance (d0) is the distance between the lens and the object (in this case, the page of print).
To find the image distance (di), we can use the lens formula:
1 / f = 1 / di - 1 / d0
Substituting the given values, we have:
1 / 6 = 1 / di - 1 / 2
Simplifying the equation, we get:
1 / di = 1 / 6 + 1 / 2 = 1 / 6 + 3 / 6 = 4 / 6
Therefore, the image distance (di) is 6 / 4 = 1.5 cm.
Now, we can calculate the magnification:
magnification = - (di / d0) = - (1.5 / 2) = -0.75
The negative sign indicates that the image is inverted compared to the object.
So, the magnification of this image is -0.75.