Question

Newton's rings equation of refractive index

Answer 1

I think six is the right answer

Answer 2

Newtons ring refractive index:-

To find the refractive index of liquid: ... Pour one or two drops of liquid whose refractive index is to be determined without disturbing the arrangement. Now the air film between the lens and glass plate is replaced by the liquid. The diameters of m+pth and mth rings are determined.