Announcements for Physics 411 (Prof. Agashe) - Fall
2014

(1). Note that HW 12.5 has been moved to HW
13.

(2). HW 13 has been
assigned here
and is due by 5
pm. outside Rm. 3118 of PSC on Thursday, December 11.

(3). HW
11 has been graded and solutions have
been posted here
(and # 12, 13 will also be done soon).

(4).
Course evaluations are due by December 14 here.

(5). Final exam is
on Monday, December
15, 8-10
am. in Rm. 1402.

(i). It will cover
all HW’s (#2-13), i.e., chapters 2-11 (except for parts that I did not discuss
in lecture).

However,
momentum in EM
fields (including Maxwell stress tensor), i.e,,
section 8.2, will not appear
on the exam

(even though I did do it in lecture and assigned HW on it).

(ii)
The exam will have **6**
problems, each with **several **parts,
just like 1st and 2^{nd} exams.

(iii) It will a closed book/notes exam, but most
math and physics **formulae** you will need will be **given
on cover sheet** of exam (a sample one is

posted here).
No other formula sheet will be
allowed.

As usual,
you are of course supposed to know what the meaning of each symbol in a formula
is, i.e., there will not be any explanation given on this sheet, e.g., H is
auxiliary field or whether a given area element is for spherical or cylindrical
coordinates.

In
addition, simple math formulae such as integral of 1 / x is log x etc. will be
assumed to be known to you.

Note that
the formulae in **actual** exam cover
sheet might be (slightly) **different**:
so the main point of above sample is to just give you an idea.

(iv) Please read the (usual) **instructions** which appear on (sample)
cover sheet carefully before you come to the exam.

(v) A **review** of topics and formulae (with
explanation) is given here.
Again, you can**not** bring the above
sheet to the exam.

(vi). A review session is scheduled
for Friday, December 12 from 3 to 5 pm. in Rm. 3150 of PSC. I plan to go
through the following list of problems during this session: HW 13.6 [which is based on example
11.2 (b) and problem 11.10/11.12 from 3^{rd}/4^{th} edition of Griffiths];

HW 13.1
(problem 9.31/9.32 from 3^{rd}/4th edition of Griffiths); HW 4.4
(problem 3.6/3.7 fro 3^{rd}/4^{th} edition of Griffiths); HW
6.3; problems 3 and 4 from 2^{nd} midterm; example 6.3 from Griffiths
and HW7.1 (problem 5.3 from Griffiths).

**(**6)**. **Outline
of plan for last 4-5 weeks of lectures is to study an application of
Maxwell's equations, namely, EM waves:

(i) we will begin with conservation
and flow of energy/momentum in EM fields (eventually in these waves): sections
8.1 and 8.2 (but I will skip angular momentum, section 8.2.4).

(ii)
Next, we will study **propagation** of waves (chapter **9**), followed by

(iii) how to solve for potentials (and fields) with time-dependent
charge/current densities (in general) from chapter **10** and

(iv) finally, apply the techniques from chapter 10 to a specific
time-dependent charge/current configuration which **creates** EM waves
(chapter **11**).

Note
that we will **skip **some
(actually, many in some cases) **parts**
in chapters **9-11** as well (I'll give
you more details as we go along)!

**(7). **More **detailed
plan**** **for lectures
for weeks just** before/after **Thanksgiving:

After

(i) **warming****-up** (section **9.1**) with waves in **1**
dimension (e.g., on string), we have started

(ii) propagation of **EM**
waves (in **3** dimensions) in vacuum
(section 9.2): we'll first do **plane**
waves

(sections 9.2.2 and 9.2.3). Then we will consider

(iii) EM
waves in **matter** (section 9.3),
including what happens when waves cross a boundary (sections 9.3.2 and
9.3.3).

We
will **skip** section 9.4 (EM Waves
in **conductors**). Then,

(iv) we come back to EM waves in vacuum, but this time **confined** ("guided") ones
(section 9.5), including rectangular wave guide (section 9.5.2)

and coaxial transmission line (section 9.5.3)

(8).
More detailed plan for last week and half of
lectures:

(a).
First, we will study how to calculate fields with time-dependent sources (in
general):

(i) We will introduce potential formulation for this purpose
(section 10.1).

(ii) We
will then compute potentials for continuous change distributions (section
10.2).

We will skip the
case of point charges (section 10.3).

(b).
Next, we will consider radiation, i.e., how EM waves are created:

(i)
introduce the
general idea (section 11.1.1) and

(ii) derive radiation of EM waves
(including the associated power) from an oscillating electric dipole
(section 11.1.2) and use this example to “justify” the general formula
for power radiated in Eq. 11.60 (from section 11.1.4)

Note
that we will skip
magnetic dipole radiation (section 11.1.3) and that from point charges (section
11.2).

(9). The
schedule/location of office hours is as follows (they are also listed on course
webpage):

(i)
By instructor:

Tuesday 2-3 pm. in Rm. 3118 of PSC

Thursday 1-2 pm. in Rm. 1304
of Toll building

(ii) By TA:

Monday:
1-2 pm. in Rm. 1304 of Toll building

Wednesday:
1.45-2.45 pm. in Rm. of
3101 of Toll building

Please
note location and day carefully. The ones in Rm. 1304 of Toll building (which is actually
a small classroom) will
be sort of informal discussion
sessions, i.e., you are not required to attend them, but it will be useful to do
so!

(10). 2^{nd}
midterm exam
scores (out of a maximum possible of 40): average 32, with standard deviation
of 8 .Solutions have been posted here.

(11). 1^{st}
midterm: solutions are posted here.
Average was 32 (out of maximum of 40), with a standard deviation of 9.5.