Question

In miyopia object distance os infinity and image distance is equal in far point =D find the focal length and which lens is used

Answer 1

We have,  

u = ∞  v =  -D  

Using Lens Formula,  

1/v - 1/u = 1/f

⇒1/-D - 1/-∞ = 1/f

⇒f=-D units

Since, f < 0 ,  

=> Lens used is concave.

Final Answer:f = -D units, Concave Lens  

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