MadSci Network: Physics |
Dear Gautam Sarker: If you imagine a very tall tree it is quite possible that there will be a temperature difference between the top and the base. Depending upon the time of the year and the location the base may be warmer or cooler than the top. A pair of thermocouple wires bonded together could generate a voltage difference between the top and the bottom of the tree. However the voltages would be very small. The larger the temperature difference the greater the voltage. However in this instance the voltages would be very small. For example if the wires are iron and constantin, the voltage generated is about 0.005 volts for a temperature difference of 100 degrees C! It is difficult to imagine a temperature difference from top to bottome of the tree being that high, so under any normal situation there would be very little use for this voltage. During a rainstorm there could be very high voltages generated between the top of the tree and the base, which is the cause of lightning bolts. However the is a situation totally out of control be man and only happens sometimes in nature and again would not have practical significance at this time. I hope this answer is clear to you. Sincerely, R. Bersin....
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