Initially there is a YDSE setup of red light and a glass slab (refractive index = 1.5) is…

Initially there is a YDSE setup of red light and a glass slab (refractive index = 1.5) is put behind one of the source now If the source is changed to green light of wavelength 10–7 m, and a new glass plate is placed in place of the previous glass plate, the central fringe shifts to a position initially occupied by the 6^th bright fringe due to red light. What will be refractive index of glass plate for the 2nd light for changed source of light?