Hello please answer and explain :

You replace the set of slits with a diffraction grating with the words "600 lines per mm" written on it. When you project light through the grating, you see only a spot of light on the screen. You move the screen closer to the diffraction grating. When the screen is at a position of 25.0 cm, you can see three spotson the screen (one on the left, one on the right, and the same white spot in the center). You realize that these three spots correspond to the bright bangs = 0, 1 and - 1 of a diffraction pattern of a diffraction grating, where the interference is constructive. You measure the distances from the center of the central fringe to the center of the bangs on the right and left :

The bright fringe on the left:1 = 10.4 cm 0.2 cm ( = 1)

The bright fringe on the right:-1 = 10.1 cm 0.2 cm ( = -1)

Figure 2 is a diagram (not to scale) showing the distance between the grating and the screen as well as the distance between the bright bangs.

25.0 cm m = 1 10.4 cm V m = 0 D 10.1 cm m = -1 Fig. 2 - Schematic of the 600 lines/mm array, the screen zen and the position of the spots.accepted - experimental % erreur * 100% accepted