Question

In a YDSE, light of wavelength \(\lambda = 5000\,\text{\AA}\) is used, which emerges in phase from two slits at a distance \(d = 3\times10^{-7}\,\text{m}\) apart. A transparent sheet of thickness \(t = 1.5\times10^{-7}\,\text{m}\) and refractive index \(\mu = 1.17\) is placed over one of the slits. What is the angular position of the central maxima of the interference pattern from the centre of the screen? Find the value of \(y\). 

• A. \(4.9^\circ\) and \(\dfrac{D(\mu-1)t}{2d}\)
• B. \(4.9^\circ\) and \(\dfrac{D(\mu-1)t}{d}\)
• C. \(3.9^\circ\) and \(\dfrac{D(\mu+1)t}{d}\)
• D. \(2.9^\circ\) and \(\dfrac{2D(\mu+1)t}{d}\)

Hint:

Insertion of a thin sheet shifts the central maxima: \[ \Delta y = D\frac{(\mu-1)t}{2d} \] Angular position depends only on path difference.

Answer 1

The Correct Option is A