A laser diode emits blue light of wavelength 4.50 × 10-7 m incident normally on a diffraction grating. A optical sensor detects the third-order diffraction maximum at an angle of 48.0∘ 48.0^\circ\,48.0∘ relative to the central zero-order maximum.
What is the number of lines per mm on this diffraction grating?
1.7×1031.7 \times 10^31.7×103
1.7×1061.7 \times 10^61.7×106
5.5×1025.5 \times 10^25.5×102
5.5×1055.5 \times 10^55.5×105
