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anonymous

  • one year ago

An electric heating coil will consume 6.0*10^2 W of power when it is connected to a 120V outlet. A greenhouse operator has 2 such coils, and she wants to construct a single heater using the two coils to keep her small greenhouse at a temperature of 50.0 C during the winter months. For how many hours must this heater (2 coils) operate per day if an average of 1.5*10^7 J of energy are required each winter day to maintain the desired temperature given that the coils are connected a) in series b) in parallel

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  1. anonymous
    • one year ago
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    What do you think the answer is?

  2. anonymous
    • one year ago
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    I really am not sure... but if I recall correctly, there is something about the parallel taking less time?

  3. imqwerty
    • one year ago
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    wait i'll give the solution.

  4. anonymous
    • one year ago
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    just show me the process step by step please

  5. imqwerty
    • one year ago
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    ok

  6. anonymous
    • one year ago
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    A)

  7. radar
    • one year ago
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    First step. Convert the 15,000,000 J to watt-hours. Use this link if you want.: http://www.unitconversion.org/energy/joules-to-watt-hours-conversion.html

  8. radar
    • one year ago
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    Next, Step 2. Calculate the wattage for both parallel and series connection. For parallel operation all is needed is to multiply the single coil power by 2 or 1200 Watts. For the series arrangement each coils is only getting 60 volts (1/2 of the 120) and since power = (e^2)/R it would be getting 1/4 their rated power or 600/4 for each coil or a total of 300 watts. You now have the needed info to make a determination of how many hours a day is needed for each configuration. The problem is asking for hours not what configuration. It is not an A or B thing lol.

  9. radar
    • one year ago
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    You will find that the series configuration will require 4 times the hours per day than the parallel configuration does

  10. radar
    • one year ago
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    How,some,ever, the cost remains the same.

  11. anonymous
    • one year ago
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    thank you for your answer, I really appreciate it =D

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