In YDSE using monochromatic light, the fringe pattern shifts by a certain distance on the screen when a mica sheet of refractive index `1.5` and thickness 2 microns is introduced in the path of one of the interfering waves. The mica sheet is then removed and the distance between the plane of slits and the screen is doubled. It is found that the distance between successive maxima (or minima) now is the same as the observed fringe shift upon the introduction of the mica sheet. Calculate the wavelength of the light.

Explanation

To solve the problem, we will follow these steps:

### Step 1: Understand the Problem
In Young's Double Slit Experiment (YDSE), we are given a mica sheet with a refractive index (μ) of 1.5 and a thickness (t) of 2 microns (2 × 10^-6 m). When this sheet is introduced, it causes a fringe shift. After removing the mica sheet, the distance to the screen is doubled, and the new fringe width equals the fringe shift caused by the mica sheet.

### Step 2: Calculate the Fringe Shift
The fringe shift (Δy) caused by introducing the mica sheet can be calculated using the formula:
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