Potential energy as a function of r is given by $U = {A \over {{r^{10}}}} - {B \over {{r^5}}}$, where r is the interatomic distance, A and B are positive constants. The equilibrium distance between the two atoms will be :
Solution
<p>For equilibrium</p>
<p>$- {{dU} \over {dr}} = 0 = {{10A} \over {{r^{11}}}} - {{5B} \over {{r^6}}}$</p>
<p>$\Rightarrow {r^5} = {{2A} \over B}$</p>
<p>And $r = {\left( {{{2A} \over B}} \right)^{1/5}}$</p>
About this question
Subject: Physics · Chapter: Properties of Solids and Liquids · Topic: Elasticity
This question is part of PrepWiser's free JEE Main question bank. 183 more solved questions on Properties of Solids and Liquids are available — start with the harder ones if your accuracy is >70%.