Ive been marked wrong but not sure why: The distance between the first and fifth minima of a single-slit diffraction pattern is 0.400 mm with the screen 41.0 cm away from the slit, when light of wavelength 570 nm is used. Find the slit width. y=m(theata)D/a m-order = 5 D-distance from slit to screen = 0.43m a-slit width = ? y-distance from centre to minima = 0.000450 m a=m(theata)D/y ((5)*(560x10^-9)*(0.43))/0.000450 = 2.6755x10^-3 The answer I got is 2.68x10^-3 but it's been marked wrong on the computer, is it me or is the answer correct??