l. The visible intensity threshold ofa night-vision device is 4.0X10'\" mez at the wavelength of 500 run. If the light with this intensity and wavelength enters an eye and the pupil is open to its maximum diameter of 8.5 mm, how many photons per second enter the eye? (25 Marks) 2. A 0.6 MeV photon is scattered by a free electron initially at rest. Alter scattering, the scattering angle of the scattered photon is 90. (i) Determine the energy and the momentum of the scattered photon. (ii) Determine the kinetic energy of the scattered electron. (25 marks)