ICSE Class 8 Answered
how do they set the power in the lense
Asked by ecoteasindia | 08 Feb, 2016, 03:48: PM
Expert Answer
The manufacturer of lenses cannot set the power of a lens. They can set the focal length of a lens.
Now, the power of a lens is reciprocal of the focal length. Hence, whatever power is desired, the reciprocal of that number is then designed as the focal length of the lens.
Example: Suppose a lens of power 2 D is to be designed. Then, the manufacturer will desing a lens of focal length
f = 1/P = 1/2 = 0.5 m = 50 cm
He will then mould the lens such that the curve of the lens corresponds to the desired focal length.
Answered by Romal Bhansali | 08 Feb, 2016, 04:41: PM
