The difference in the number of wavelengths, when yellow light propagates through air and vacuum columns of the same thickness, is one. The thickness of the air column is: (Refractive index of air μa=1.0003,Wavelength of yellow light in vacuum = 6000 ∘A)
A. 1.8 mm
B. 2 mm
C. 2 cm
D. 2.2 cm