a lens of focal length f is cut into two equal parts without affecting its curvature. the two pieces will have equal focal length of 
(a)f
(b)2f
(c)f/2
(d)f/3
explain

Asked by Rida Mukadam | 26th Feb, 2015, 10:15: PM

Expert Answer:

begin mathsize 14px style straight A space lens space of space focal space length space straight f space is space cut space into space two space equal space parts space without space affecting space its space curvature. space Each space part space will space have space focal space length space will space be 1 over straight F space equals space 1 over straight f space plus space 1 over straight f rightwards double arrow space straight F space equals space straight f over 2  When space space lens space is space cut space vertically space then comma space each space part space wil space have space focal space length colon space space 1 over straight f space equals space fraction numerator 1 over denominator straight f apostrophe end fraction space plus space fraction numerator 1 over denominator straight f apostrophe end fraction straight f apostrophe space equals space 2 straight f end style

Answered by Priyanka Kumbhar | 27th Feb, 2015, 09:50: AM

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