A doctor has prescribed a corrective lens of power +1.5D. Find the focal length of the lens. Is the prescribed lens diverging or converging ?
Answers
Answered by
19
Given,
Power of lens = +1.5D (D - dioptre)
Let the focal length be f.
Power of lens = 1/focal length (in metres)
= 100/focal length (in centimetres)
1.5 = 100/f
=> f = 100/1.5
=> f = 1000/15
=> f = 66.67m
Focal Length = +66.67m
As,the focal length is positive, it is convex lens.So, the lens is convergent in nature.
The Prescribed Lens is Converging in nature.
Answered by
36
Power of lens = +1.5D
So,
1.5 = 100/f
f = 100/1.5
f= 1000/15
f= 66.67m
Therefore,the prescribed lens is converging in nature.
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