Chapter 21 Problem 63

Problem

The HCl molecule has a dipole moment of about $3.4\times 10^{-30}{\textrm {C\cdot m}}$. The two atoms are separated by about $1.0\times 10^{-10}{\textrm {m}}<math>.(a)Whatisthenetchargeoneachatom?(b)Isthisequaltoanintegralmultipleof<math>e$? If not, explain.

(c) What maximum torque would this dipole experience in a $2.5\times 10^{4}{\textrm {N/C}}$ electric field?

(d) How much energy would be needed to rotate one molecule 45° from its equilibrium position of lowest potential energy?

Solution

(a)

$p=Ql\rightarrow Q={\frac {p}{l}}={\frac {3.4\times 10^{-30}{\textrm {C\cdot m}}}{1.0\times 10^{-10}{\textrm {m}}}}=3.4\times 10^{-20}{\textrm {C}}$