$1.-$A diffraction grating is just barely able to resolve light from two sources with wavelengths $601\mathrm{.}5$ nm and $603\mathrm{.}5$ nm $.$ Could the same diffraction grating be able to resolve light from two sources with wavelengths $540\mathrm{.}2$ nm and $540\mathrm{.}4$ nm $.[$Assume the spot sizes on the grating of all four sources are identical.$]$