Modern Physics

JEE Main level, single correct, medium

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Question 5 of 5

The de-Broglie wavelength of a thermal neutron at temperature TT is inversely proportional to:

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Answer: (A) T\sqrt{T}

Kinetic energy E=32kBT  ⟹  λ=h2mE=h3mkBT∝1TE = \frac{3}{2} k_B T \implies \lambda = \frac{h}{\sqrt{2mE}} = \frac{h}{\sqrt{3m k_B T}} \propto \frac{1}{\sqrt{T}}.

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