Report on Short Option S8 Covariant Electromagnetism            2004


Number of Candidates 43


Question 1
33 attempts   Mean 19.0   Std Dev 6.9   Max mark 25

A straightforward question apart from the fact that no intermediate results
were given, and correspondingly popular. The mark distribution was bimodal,
with a large group obtaining full or nearly full marks, and a small group with
approximately half marks who did not obtain the correct answer to the first
part of the question and were thereby prevented from continuing successfully.


Question 2
17 attempts   Mean 11.3   Std Dev 6.7   Max mark 21

A question with several parts of graded difficulty. Only 2 candidates came
close to recognizing the need to transform the $r$, $t$ dependence of the
potentials to $r'$, $t'$ before differentiating to find the field in the primed
frame, and consequently there were 5 marks essentially unobtainable for most 
candidates.


Question 3
21 attempts   Mean 12.0   Std Dev 3.1   Max mark 18

The first few marks were very easy, which perhaps tempted candidates unable to
attempt the later parts. As in question 2, very few candidates were aware of
the necessity to convert the $r$, $t$ dependence of the potentials to $r'$, 
$t'$, and this led to almost no correct answers to the middle part. I
re-weighted the first two sections to allow me to give credit to candidates
obtaining correct intermediate results in the middle section.


Question 4
15 attempts   Mean 13.7   Std Dev 7.3   Max mark 25

Although algebraically lengthy this question was not otherwise difficult, and
there were a reasonable number of essentially correct attempts.