1. An electron is accelerated from rest through 72.5 kV. a) How much kinetic energy does it gain (in joules)? b) If the electron transfers all of its energy into a single photon, what is the frequency and wavelength of this photon? 2. A device is sensitive to wavelengths up to 900 nm. a) What is the work function of this device? b) If light of wavelength 700 nm enters the device, what is the kinetic energy of the electrons given off