In a Young’s double slit experiment, an angular width of the fringe is \( 0.35^\circ \) on a screen placed at \( 2 \, \text{m} \) away for particular wavelength of \( 450 \, \text{nm} \). The angular width of the fringe, when whole system is immersed in a medium of refractive index \( 7/5 \), is \( \dfrac{1}{\alpha} \). The value of \( \alpha \) is __________.
