In a Young’s double-slit arrangement, the distance between the 3rd bright fringe and the 5th dark fringe on the same side of the centre is measured to be 1.8mm. The slits are 0.30mm apart and the screen is 1.2m away. Estimate the wavelength of the light used.
(a) 200nm
(b) 450nm
(c) 300nm
(d) 225nm