2. Atomic Structure

Interatomic Forces — Quiz

Test your understanding of interatomic forces with 5 practice questions.

Practice Questions

Question 1

In the Lennard-Jones potential $U(r)=4\epsilon\left[\left(\frac{\sigma}{r}\right)^{12}-\left(\frac{\sigma}{r}\right)^{6}\right]$, what is the value of $U(r)$ when $r=\sigma$?

Question 2

At the distance $r=\sigma$ in the Lennard-Jones potential, is the interatomic force $F(r)=-\frac{dU}{dr}$ attractive, repulsive, zero, or undefined?

Question 3

What physical significance does the parameter $\sigma$ have in the Lennard-Jones potential?

Question 4

In the Lennard-Jones potential curve, for which range of $r$ are atoms in a bound state (i.e., $U(r)<0$)?

Question 5

In a generic potential energy curve $U(r)$, which region (in terms of $r$ relative to the equilibrium separation $r_0$) corresponds to strong short-range repulsion?