Light from an argon laser strikes a diffrac- tion grating that has 4750 lines/cm. The central and first-order principal maxima are separated by 0.436 m on a wall 1.55 m from the grating.

Find the wavelength of the laser light.

1. 285.033 nm
2. 7774.77 nm.
3. 1140.13 nm
4. 1097.54 nm
5. 2105.26 nm
6. 570.066 nm
7. 144.205 nm