HW2 - 5. A metal surface illuminated by 8.5 x 10 14 Hz...

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Chapter 2 Homework Problems 1. If Planck’s constant were larger than it is, would quantum phenomena be more or less conspicuous than they are now? 2. (a)A typical AM radio frequency is 1000kHz. What is the energy in eV of photons of this frequency? (b) What is the energy of the photons in an FM signal of frequency 100 MHz? 3. A 1.00-kW radio transmitter operates at a frequency of 880kHz. How many photons per second does it emit? 4. A typical chemical bond in a biological molecule has strength of a few eV – let’s say 4 eV to be specific. (a) Can low intensity microwave radiation with wavelength 1 cm break a bond, thus causing a mutation in a DNA molecule? (Very high – intensity microwave radiation, such as is found inside a microwave oven, will heat biological tissue, thus causing burn damage.) (b) What is the minimum wavelength necessary for a photon to be able to break a 4-EV chemical bond? (c) What type of photon has this minimum wavelength? (Blue? IR? Other?)
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Unformatted text preview: 5. A metal surface illuminated by 8.5 x 10 14 Hz light emits electrons whose maximum energy is 0.52eV. The same surface illuminated by 12.0 x 10 14 Hz light emits electrons whose maximum energy is 1.97eV. From these data find Plancks constant and the work function of the surface. 6. Potassium chloride (KCl) has a set of crystal planes separated by distance d = 0.31 nm. At what glancing angle to these planes would the second order Bragg maximum occur for X-rays of wavelength 0.05 nm? 7. What is the voltage of an X-ray tube that produces X-rays with wavelengths down to 0.01 nm but no shorter? 8. An x-ray photon of initial frequency 3.0 x 10 19 Hz collides with an electron and is scattered through 90 o . Find its new frequency. 9. Find the change in wavelength for photons scattered through 180 o by free protons. Compare with the corresponding shift for electrons. Is this larger or smaller than an electron scattered at 90 o ?...
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