Lens Formula: The lens formulagives the relation between image distance, object distance and focal length. The lens formula is given by:
Where
v = image distance
u = object distance
f = focal length
The lens formula is true for all situations with appropriate sign conventions.
Similar to the magnification produced by mirrors, magnification produced by lenses is the ratio of height of image to height of object. It can be represented as:
or = m =
Where
m = magnification
h2 = height of image
h1 = height of object
The linear magnification produced by a lens is equal to the ratio of image distance to the object distance. That is:
Where
m = magnification
v = image distance
u = object distance
Important notes on magnification:
(i)The positive sign shows that the image is erect and virtual
(ii)The negative sign shows that the image is real and inverted
For a spherical lens, remember for the linear magnification (m):
Virtual positive, real negative.
Or
Where P = Power of the lens
And f = focal length of the lens (in metres)
Start your learning Journey !