A) Astronomers measure the peak wavelength of a nearby star to be 410 nm. What is the star's temperature? B) How much energy does a single photon of light have at this wavelength? C) An electron bound in an unknown metal requires 1.45E-19 ] of energy under the photoelectric effect to become free of the metal. How much kinetic energy would it have if struck by the photon froft part (b)? D) What is the final speed of the elctron from part (c)

Calculate the de Broglie wavelength a)an electron with kinetic energy 50eV. b) an proton with kinetic energy 50eV. c) a 100 g bullet moving at 1200 m/s.

A certain X-ray machine generates X-rays from a beam of electrons accelerated from zero to 99.9999999 per cent the speed of light in a long linear accelerator of length 3.2 km. The electrons are generated in pulses of duration ∆t = 100 fs. The generated x-rays from the target are also short pulses (λ = 0.15 nm). Determine the energy of a single x-ray photon in the beam. a.) 8.27 eV              b.) 8.27 J                           c.) 8.27 keV                     d.) none of these.

Tantalum has a work function of 4.2 eV. The most energetic photoelectron has KE of 2.12 eV. What is the wavelength of the incoming photons? a) 586 nm                            b) 197 nm                       c) 296 nm                        d) none of these.