How many photons are contained in a flash of green light 525nm that contains 189KJ of energy?

To find the number of photons, we need to first calculate the energy of one photon using the formula E = hc/λ, where E is energy, h is Planck's constant, c is the speed of light, and λ is the wavelength. Then, we can divide the total energy (189 kJ) by the energy of one photon to get the total number of photons in the flash of light.