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Physics, 28.09.2019 21:10 Angel1107

Photons section 3.3.3 reviewed timofeett's empirical result that the rate of induced mutations is nroportional to the radiation dose. not only x-rays can induce mutations: even ultraviolet light will work (thats why you wear sunblock). to get a feeling for what is so shocking about timof'eeff's result, notice that it implies there's no "safe," or threshold, dose level. the amount of damage (probability of damaging a gene) is directly proportional to the dose (total amount of radiation exposure). extrapolating to the smallest possible dose, this means that even a single photon of uv light has the ability to cause permanent, heritable, genetic damage (albeit with some very low probability). a somebody tells you that a single ultraviolet photon carries an energy equivalent of ten electronvolts (ev, see appendix b). you suspect that the damage mechanism is that a photon delivers that energy into a volume the size of the cell nucleus and heats it up: then the increased thermal motion knocks the chromosomes apart in some way. is this a reasonable proposal? why or why not? (hint: use equation 1.2, and the definition of calorie found just below it, to calculate the temperature change.] b. turning the result around, suppose that that photon's energy is delivered to a small volume ls and heats it up. we might suspect that if it heats up the region to boiling, that be in order for this would disrupt any message contained in that volume. how small must amount of energy to heat that volume up to boiling (from 30. c to 100. c)? what could we conclude about the size of a gene if this proposal were correct?

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Photons section 3.3.3 reviewed timofeett's empirical result that the rate of induced mutations is nr...
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