Question

Two glasses with refractive indices of 1.5 and 1.7 are used to make two identical double convex lenses how will each of these lenses act on a ray parallel to its optical axis

Answer 1

Answer:

Number of glasses -2

1/fa =(1.5 - 1)(1/R1 - 1/R2) ----(1)

1/fa =(1.5 - 1)(1/R1 - 1/R2) ----(1)1/fb =(1.7 - 1)(1/R1 - 1/R2) -----(2)

1/fa =(1.5 - 1)(1/R1 - 1/R2) ----(1)1/fb =(1.7 - 1)(1/R1 - 1/R2) -----(2)On dividing EQ(2) by EQ {1)

we get,

fa/fb = 7/5