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Homework Help: Area of a Gold Leaf?

  1. Sep 2, 2011 #1
    1. The problem statement, all variables and given/known data

    Gold, which has a density of 19.32 g/cm^3, is the most ductile metal and can be pressed into a thin leaf or drawn out into a long fiber. (a) If a sample of gold, witha mass of 27.63g, is pressed into a leaf 1.000 µm thickness, what is the area of the leaf? (b) If, instead, the gold is drawn out into a cylindrical fiber of radius 2.500 µm, what is the length of the fiber?

    2. Relevant equations

    ρ=m/V and others?

    3. The attempt at a solution

    Not sure what to do. Got volume but how do i use that to get area? I also do not know what equations would apply to a gold leaf.
  2. jcsd
  3. Sep 2, 2011 #2
    isnt volume =area * thickness
  4. Sep 2, 2011 #3
    Yes, if i assume that it is a cube or rectangular prism.
    is that right?
  5. Sep 3, 2011 #4


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    Staff Emeritus
    Science Advisor
    Homework Helper

    In general, a prism does not have to be rectangular in cross section for the volume relation to hold, so long as all cross sections are similar. For the gold leaf, the thickness is so small, it would be reasonable to assume that the areas of the front and back of the leaf are equal, hence the leaf could be considered to be a very short prism.
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