Agamma-ray photon produces an electron and a positron, each with a kinetic energy of 261 kev . h=6.626×10−34j⋅s, c=2.998×108m/s, me=9.109×10−31kg, e=1.602×10−19c.
a) determine the energy of the photon. b) determine the wavelength of the photon.

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Electroplating is a way to coat a complex metal object with a very thin (and hence inexpensive) layer of a precious metal, such as silver or gold. in essence the metal object is made the cathode of an electrolytic cell in which the precious metal cations are dissolved in aqueous solution. suppose a current of 480.ma is passed through an electroplating cell with an aqueous solution of agno3 in the cathode compartment for 46.0 seconds. calculate the mass of pure silver deposited on a metal object made into the cathode of the cell. round your answer to 3 significant digits. also, be sure your answer contains a unit symbol. ×10μ

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.