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    how do you find the minimum velocity an object of mass m, has to travel to be diffracted through a slit of length d?
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    Use DeBroglies formula with p=mv.
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    Isn't this physics, not maths?

    Anyway yeah using λ = h/(m.v).

    Combine it with diffraction formula, substituting to cancel out λ:

    λ = dsinθ

    Where θ is the angle of diffraction.

    Which would give:

    dsinθ = h/(m.v)

    v = h/(m.d.sinθ )

    Not to sure how you'd go about finding some sort of minimum velocity. I guess you would say the angle is 90° maybe?
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    at sinθ = 90° (that's what i did)

    λ = d

    lets say d is 1meter

    m is 1kg

    then, v = h/mλ
    therefore, v = h/m, which seems pretty slow to me
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    h is something like 10^{-34} but m is about 10^{-19} and d is typically 10^{-8} or something like that.

    You can't put in d=1, m=1 and expect a sensible answer. h is a quantum constant, so you have to put in quantum sized lengths to expect a sensible answer.
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    hmm, the question was "what's the velocity a person has to walk to go diffract through a doorway"
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    Then you're supposed to get a silly answer. And in case anyone's worried, walking slowly through a doorway won't diffract you all over the walls It's just a negligibly small possibility...
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    haha right, thanks then
 
 
 
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