Medium INTEGER +4 / -1 PYQ · JEE Mains 2021

A particle of mass m moves in a circular orbit in a
central potential field U(r) = U0r4. If Bohr's quantization conditions
are applied, radii of possible
orbitals rn vary with ${n^{{1 \over \alpha }}}$, where $\alpha$ is ____________.

Answer (integer) 3

Solution

$\overrightarrow F = - {{d\overrightarrow u } \over {dr}}$<br><br>$= - {d \over {dr}}({U_0}{r^4})$<br><br>$\overrightarrow F = - 4{U_0}{r^3}$<br><br>$\because$ ${{m{v^2}} \over r} = 4{U_0}{r^3}$<br><br>$m{v^2} = 4{U_0}{r^4}$<br><br>Then $v \propto {r^2}$<br><br>$\because$ $mvr = {{nh} \over {2\pi }}$<br><br>Then ${r^3}\propto\,n$<br><br>$r\,\propto \,{(n)^{{1 \over 3}}}$<br><br>So the value of $\alpha = 3$

About this question

Subject: Physics · Chapter: Atoms and Nuclei · Topic: Bohr's Model of Hydrogen Atom

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