Physics
posted by Lexi on .
Diffraction grating #1 has half the lines/cm that diffraction grating #2 does. When used with a certain wavelength of light, both gratings give first order maxima. Which of the following statements is true for the same wavelength of light.

Grating #2 must give a second order maximum.
Both gratings must also give second order maxima.
It is possible that neither grating gives a second order maximum.
Grating #1 must give a second order maximum. 
Grating #1, which has less dispersion, will have a second order maximum where grating # 2 has its first order maximum.
Choose the last answer.