An equiconvex lens is cut into two identical plano convex lens. What is the ratio of focal lengths of equiconvex lens to that of plano convex lens...?
 

Asked by nayonikamenon15 | 11th Jan, 2016, 12:33: AM

Expert Answer:

Let the focla legth of the equiconvex lens be f and of each identical plano convex lens be f'
For the equiconvex lens, the focal length is 

begin mathsize 12px style 1 over straight f equals open parentheses straight mu minus 1 close parentheses open parentheses 1 over straight R plus 1 over straight R close parentheses equals fraction numerator 2 open parentheses straight mu minus 1 close parentheses over denominator straight R end fraction For space each space identical space plano space convex space lens comma space the space focal space length space is fraction numerator 1 over denominator straight f apostrophe end fraction equals fraction numerator open parentheses straight mu minus 1 close parentheses straight R over denominator 2 end fraction equals fraction numerator 1 over denominator 2 straight f end fraction therefore straight f apostrophe equals 2 straight f or space fraction numerator straight f over denominator straight f apostrophe end fraction equals 1 half end style

Answered by Yashvanti Jain | 11th Jan, 2016, 06:23: PM