In a Young’s double slit experiment, a combination of two glass wedges \( A \) and \( B \), having refractive indices \( 1.7 \) and \( 1.5 \), respectively, are placed in front of the slits, as shown in the figure. The separation between the slits is \( d = 2 \, \text{mm} \) and the shortest distance between the slits and the screen is \( D = 2 \, \text{m} \). Thickness of the combination of the wedges is \( t = 12 \, \mu \text{m} \). The value of \( l \) as shown in the figure is \( 1 \, \text{mm} \). Neglect any refraction effect at the slanted interface of the wedges. Due to the combination of the wedges, the central maximum shifts (in \( \text{mm} \)) with respect to \( 0 \) by ____.
