energy rate query?

Discussion in 'General Science & Technology' started by damarco, Dec 4, 2008.

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  1. damarco

    damarco Registered Member

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    Hi all, Nearly all of the energy used on earth comes originally from the sun, and that solar radiation is intercepted at 1370 Wm^-^2 at the top of the atomsphere, and that 49%of this radiation is absorbed by the earths surface. If a shallow dish containing ice or warte, placed on the earth surface, absorbs the same the same fraction of solar radiation as the surface itself, at what rate is energy absorbed from the sun by such a container of surface 0.039m^2 ?
    Can you show me how thhis is worked out please.

    thanks damarco.
     
    damarco, Dec 4, 2008
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  3. ElectricFetus

    ElectricFetus Sanity going, going, gone Valued Senior Member

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    say again?
     
    ElectricFetus, Dec 4, 2008
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  5. Fraggle Rocker

    Fraggle Rocker Staff Member

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    This looks like a notational error. I assume you meant to type 1370 W/m^2 ( 1370 watts per square meter ), rather than an East Asian "happy face" emoticon. ^_^ =

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    So isn't your answer simply the product of 1370 x .49 x .039 = 26.2 watts? Am I missing something here?

    On SciForums we normally encourage a policy of not doing people's homework for them. But in this case the problem looks so simple, I don't understand why you had to ask.

    BTW, I did not check your figures and I have no idea if that answer is the actual rate of solar energy absorption at sea level. It's merely the correct result of the calculation you presented.

    Please elaborate. I'm sure there's a communication gap here and the problem is not as simple as it looks.
     
    Fraggle Rocker, Dec 5, 2008
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  7. kevinalm

    kevinalm Registered Senior Member

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    1366w/m^2 is the value of the solar constant given in Wikipedia. Of course you should correct for non normal incidence and other factors, but for a simple exercise, his number isn't too bad.
     
    kevinalm, Dec 5, 2008
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