A double convex lens has two surfaces of equal radii 'R' and refractive index n= 15.Find the focal length 'f'.
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Answered by
20
1f=(n-1) [(1/R1) -(1/R2)]
put the values u will get ur answer
put the values u will get ur answer
Sombarna2004:
sorry u can do it by ur own try just
then
i had said the formula its only the key thing to do
i am right or not?
Answered by
22
hey mate.....☺️☺️☺️☺️
Using lens makers formula, 1/f=(n-1)[(1/R1)-(1/R2)] Here n=15, R1= R and R2= -R Therefore, 1/f=(15-1)[(1/R)-(1/-R)] =>. 1/f= 14×[2/R] =>. 1/f= 28/R =>. f = R/28
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