1. Thermal Radiation Which of the following is true of thermal (blackbody) radiation? A.Only very hot objects give off thermal radiation. B.All objects give off the same types of thermal radiation, but hotter objects give off more radiation. C.All objects give off thermal radiation, but hotter objects give off more and higher frequency radiation.

2. Duality The longer the wavelength of light, the ___ the energy of the photon. The longer the wavelength of an electron wave, the ___ the energy of the electron. A.higher, higher. B.lower, higher C.higher, lower D.lower, lower

3. Wavefunction When a beam of light is sent through a pair of slits, bright spots are formed on a screen at points that I label B for “bright,” and dark spots are formed at points I label D for “dark.” I am likely to find a lot of photons at points labeled ___, and few at points labeled ___. A.D, B B.B, D

4. Wavefunction When a beam of light is sent through a pair of slits, bright spots are formed on a screen at points that I label B for “bright.” If I now send a single photon in the same way through these same slits, and look to see where the photon arrives at the screen, then A.I am likely to find the photon at one (and only one) of the points labeled B. B.I may find the photon’s energy split among one or more points labeled B, but not necessarily all of them. C.I will find the photon’s energy split among all the points labeled B.

5. PAL Week 7 Wednesday 500-nm light strikes a metal with a workfunction of 1.7 eV. A.Find the energy of one photon of the light. 2.48 eV B.How much energy is absorbed by one electron in the metal that absorbs light? 2.48 eV C.Will that electron escape the metal? (Justify, of course.) yes –energy absorbed>workfunction D.If so, find its kinetic energy (assume max). 0.78 eV E.Find the wavelength of the electron after it escapes the metal. 1.39 nm mass of electron = 9.11X10 -31 kg = 511keV/c 2 h=6,626X10 -34 Js hc=1240eVnm