Light from a laser strikes a diffraction grating that has 5 308 grooves per centimeter. The central and first-order principal maxima are separated by 0.488 m on a wall 1.88 m from the grating. Determine the wavelength of the laser light. (In this problem, assume that the light is incident normally on the gratings.) nm

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?