# AdvEMpset2.pdf - September 1 2017 Cornell University...

• Homework Help
• 3

This preview shows pages 1–2. Sign up to view the full content.

September 1, 2017 Cornell University, Department of Physics PHYS 3327, Advance E&M, HW # 2, due: 9/6/2017, 11:15 AM Question 1 : The dipole Consider a system as discussed in class and shown in Fig. 2.1 in Heald & Marion. 1. Write down the exact potential and expand it in the appropriate small parameter to obtain the result we showed in class, which is that to leading order Φ( r ) = 2 q‘ cos θ r 2 (1) 2. Derive the electric field from Eq. (1). Show that E φ = 0 and write E r and E θ explicity. 3. Argue that the result E φ = 0 is exact and is not a result of the dipole approximation. 4. Find specific values of θ where you can argue that the result of E r or of E θ are exact. You should not need to do any complicated calculations involving the exact potential. Instead, use general physical arguments. 5. Explain why the relative correction to E r due to higher order terms that we neglected scales like ( ‘/r ) 2 , rather than like ( ‘/r ) as we might naively expect. As an example, while the lowest order term contains ( ‘/r ), the next lowest order term contains ( ‘/r ) 3 rather than ( ‘/r ) 2 . 6. We now move the origin a bit, that is O new = O old + a , so that there are only small corrections to the results we have obtained so far. Please define, in words, what “a bit” means. (It might help to answer the next part of the question first.)

This preview has intentionally blurred sections. Sign up to view the full version.

This is the end of the preview. Sign up to access the rest of the document.
• Fall '10
• Cohen

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern