Therefore, the number of photons reaching the negative film per second is × 10 6.

If photons arrive at the negative film in turn, the time interval between two adjacent photons in the beam arriving at the negative film is

The average distance between two adjacent photons is s = c △ t = 3.0×108× 8.0×10-7m = 2.4×102m.

(2) According to the calculation result of (1), the distance between two photons is 2.4×10.2 m, and the length of the box is only10.2 m, so it is generally impossible for two photons to move in the box at the same time. This excludes the possibility that the diffraction behavior of light is photon interaction. Therefore, the appearance of diffraction pattern is the result of the accumulation of many photons' independent behaviors. In the bright areas of diffraction fringes, photons are more likely to arrive, while in the dark areas, photons are less likely to arrive. This experiment supports the view that light waves are probabilistic waves.