16. An X-ray photon with a wavelength of 3.97 x 10- m collides with an electron. The wavelength of the photon after it scatters at an angle of 25.0 is: A. 3.95 x 10-11 m. B. 2.27 x 10-13 m. C. 3.97 x 10-11 m. D. 3.99 x 10-1' m. 17. A photon with an initial energy of 33.0 eV collides with an electron. If the speed of the electron after the collision is 4.56 x 10' m/s, the final energy of the photon is: A. 32.4 eV B. 33.0 eV C. 33.6 eV D. 0.592 eV 18. A student challenged the concept of matter waves on the basis that she never observed wave properties of a hockey puck as it moved toward her in the goalie net. The best explanation that her teacher can provide is that: A. the black puck is a perfect black body radiator. B. the frequency of the puck is too low to detect. C. the wavelength of the puck is too short to observe. D. the puck is travelling too fast to observe its wave properties. 19. The work functions for some common metals are listed in the table below. cesium 2.1 eV copper 4.7 eV iron 4.5 ev sodium 2.3 eV Visible light could be used to emit photoelectrons from which metals? A. cesium, sodium, and iron A B. iron and copper C. cesium and sodium D. sodium, iron, and copper