In Young's double slit experiment, the distance between the slits and the screen is $$1.2 \mathrm{~m}$$ and the distance between the two slits is $$2.4 \mathrm{~mm}$$. If a thin transparent mica sheet of thickness $$1 \mu \mathrm{m}$$ and RI 1.5 is introduced between one of the interfering beams, the shift in the position of central bright fringe is