Yellow-green light(wavelength 550nm) passes through two closely spaced very narrow slits, producing bright interference fringes separated by 4.50mm on a screen 3.00m from the slits.
A. How far apart are the slits
B. A second light source used with the same slits and screen causes bright fringes separated by 4.00 mm, what is the wavelength for that second source of light.