In Concept Exercise 24.5, we found that a water molecule is made up of two hydro
ID: 1661607 • Letter: I
Question
In Concept Exercise 24.5, we found that a water molecule is made up of two hydrogen atoms and one oxygen atom, for a total of 10 electrons and 10 protons. The molecule is modeled as a dipole with an effective separation d = 3.9 1012 m between its positive and negative charges. The water molecule's dipole moment is p = 6.2 1030 C · m. Consider water molecules in the lower atmosphere where the electric field has a magnitude of about 335 N/C. Assume the field is uniform. Find the magnitude of the angular acceleration for the water molecule. (Enter the maximum possible angular acceleration.) rad/s2
Explanation / Answer
Given
dipole moment is p = 6.2*10^-30 C.m
the electric fieldis E = 335 N/C
we know that the torque T = PXE = P*E sin theta
the maximum torque is when the angle theta is 90 degrees so
the torque is T = P*E
T = 6.2*10^-30*335 N.m
T = 2.077*10^-27 N.m
the torque is T = 2.077*10^-27 N.m