(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A plano-convex lens having a radius of curvature of r = 4.00m is placed on a concave glass surface whose radius of curvature is R = 12.0 m. Determine the radius of the 100th bright ring, assuming 500-nm light is incident normal to the flat surface of the lens.

2. Relevant equations

Kinda need to derive your own here. What I came up with was r - sqrt(r^{2}- s^{2}) - R + sqrt(R^{2}- s^{2}) = (m+.5)lambda/(2n_{film})

s is the radius of the mth bright ring, lambda is the wavelength of light, n_{film}is 1 for this problem since I assume the film is air

3. The attempt at a solution

Plugging in numbers I get this.

I have no idea how to solve that equation without a calculator/computer, but I guess my answer would be 1.74 cm. Could be right, could be wrong.

Any ideas on this? Thanks in advance.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Newton's Rings

Can you offer guidance or do you also need help?

Draft saved
Draft deleted

**Physics Forums | Science Articles, Homework Help, Discussion**