[" Q.What fresh problem now disturbs Mme Loisel? "]

What is a primary disturbance?

What do M. and Mme Loisel do next?

What kind of a person is Mme Loisel − why is she always unhappy?

In the above problem, now a liquid is poured into the vessel and filled up to OQ. The central bright fringe is found to be at Q. The refractive index of the liquid is