Youngs Double Slit Experiment

In Young's double slit experiment, slit separation is 0.6 mm and the separation between slit and screen is 1.2 m. The angular width is (the wavelength of light used is 4800 )

In Young's double slit experiment, fringes of width are produced on the screen kept at a distance of 1 m from the slit. When the screen is moved away by m, fringe width changes by m. The separation between the slits is m. The wavelength of light used is .................... nm.