Substances can undergo physical changes or chemical changes. what is the difference between these two kinds of changes

Two lasers are shining on a double slit, with slit separation d. laser 1 has a wavelength of d/20, whereas laser 2 has a wavelength of d/15. the lasers produce separate interference patterns on a screen a distance 5.30 m away from the slits. part a which laser has its first maximum closer to the central maximum? view available hint(s) which laser has its first maximum closer to the central maximum? laser 1 laser 2