Final Exam Review W18.pdf - PHY 1002 Final Exam Review Part A Calculations 1 An energy level diagram for a particular atom shows three distinct energy

# Final Exam Review W18.pdf - PHY 1002 Final Exam Review Part...

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PHY 1002 Final Exam Review Part A - Calculations 1. An energy level diagram for a particular atom shows three distinct energy levels: E 0 = 0.0 eV, E 1 = 3.2 eV and E 2 = 4.6 eV. a. What is the energy released during transition from E 2 to E 1 ? What is the frequency? What is the wavelength? What type of EMR is this? b. What is the energy released during transition from E 1 to E 0 ? What is the frequency? What is the wavelength? What type of EMR is this? 2. A microwave transmission of frequency 7.85 GHz is bounced off a satellite back to earth. The height of the satellite is 825 km. What was the speed of the microwave signal? 3. Microwave heat therapy is used for deep heating. Such a device operates at 2450 MHz and emits 7.83 x 10 26 photons/sec. A patient wishes to heat up a 4.4 kg region in the lower back by 7.5 ° C using this treatment. Assuming that 85% of the photons hit the target area, and 51% of these are absorbed, how long (in seconds) must this device be on to do this? Assume that the specific heat of tissue is 0.83 kcal/kg·°C 4. What is the energy in eV of 3.85 x 10 15 Hz ultraviolet (UV) radiation? 5. What particle is emitted in each of the following nuclear reactions? a. Gold-198 decays to mercury-198 b. Radon-222 decays to polonium-218 c. Cesium-134 decays to xenon-134 6. A person goes to have a chest x-ray. The machine emits 2.9 x 10 10 photons/sec, these photons have a frequency of 4.9 x 10 19 Hz. The x-rays hit a 4.5 kg region in the chest. 95% of the photons emitted hit the chest and 50% are absorbed. The device is on for 0.75 sec. What temperature rise would one expect in this region after the x-ray? 7. What is the wavelength of a photon carrying energy of 6.65 eV? What type of EMR is this? 8. Tritium, a radioactive isotope of hydrogen, has a half-life of 12.3 years. a. In 49.2 years, how many half lives will this isotope experience? b. If you started with an initial sample of 1.5 mg, how much will be left (in mg) at the end of this period? c. How much tritium will be remaining (from the original 1.5 mg) after a period of 70 years? d. How long (in years) would it take for the sample to decay to 0.045 mg? 9. During an x-ray lasting 0.46 seconds, how much energy (in joules) has the x-ray machine emitted if the EMR frequency was 1.28 x 10 19 Hz and the photons were emitted at a rate of 4.3 x 10 11 photons/sec?

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10. K-38 decays to form Ar-38 and has a nuclear half-life of 7.7min and a biological half-life of 4.2min.

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