[填空题]
White light containing wavelengths from 478m dg j pgw(l,6jqaa3uw7y/e10 2 bc70gjc* eb: oh(dvvyv 7ld;zsqz32 nm to 750 nm falls on a grating with g7h zz so3b:d2cj;v qv(eb7cdy20v*l $8500\;lines/cm$ How wide is the first-order spectrum on a screen 2.30 m away? m
