Basic Newton's Rings Numerical Problem

[sayansh]

In Newton's Rings Experiment, what will be the order of the dark ring which will have double the diameter of that of the 20th dark ring? Wavelength(lambda = 5890 Angstrom); Radius of curvature is not given. Thin film is made of air, so refractive index is 1. And the light is incident normally (90 degrees)Difference between squares of diameters = 4R(lambda){m - n} m is the order of the higher order ring (the ring we have to find in this case), and n is the order of the ring we know (20). Also, Diameter square/4*Radius of Curvature = order of the ring*wavelength
Tried finding radius of curvature in terms of diameter square and later substituting in first equation, but was left with 2 variables and 1 equation, tried substituting values in first equation but again was left with 2 variables in 1 equation. Is there another way of solving this that i am missing? Help would be really appreciated..

 

[Sweta]

I am getting in fraction
What is the answer actually

 

[gneill]

This is an old thread from 2010, and the Original Poster (sayansh) made just the one post and never returned.

@Sweta : If you would like help with this or a similar problem, please start a new thread of your own. Be sure to use the provided formatting template and show us what you've tried.

 

[Sweta]

@gneill actually I tried it but I am not getting the answer
Can u pls solve it??

 

[gneill]

@gneill actually I tried it but I am not getting the answer
Can u pls solve it??

That's not how things work here. Please read the forum rules (which you agreed to abide by when you joined). Also take a look at:

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