Recent content by wang jia le

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    I How Do Supremum and Infimum Relate When s < t for All s in S and t in T?

    Let S and T be subsets of R such that s < t for each s ∈ S and each t ∈ T. Prove carefully that sup S ≤ inf T. Attempt: I start by using the definition for supremum and infinum, and let sup(S)= a and inf(T)= b i know that a> s and b< t for all s and t. How do i continue? , do i prove it...
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    De broglie wavelength for helium and distance between atoms

    Homework Statement Consider a balloon filled with helium gas at room temperature (T = 294 K) and atmospheric pressure. Calculate (a) the average de Broglie wavelength of the helium atoms and (b) the average distance between atoms under these conditions. The average kinetic energy of an atom is...
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    Power and rate of photon emission with a given temperature

    Assuming that your surface temperature is 99.1 F and that you are an ideal blackbody radiator (you are close), find (a) the wavelength at which your spectral radiancy is maximum,(b) the power at which you emit thermal radiation in a wavelength range of 1.0 nm at that wavelength, from a surface...
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