AP Exam Suggestions
Physics is not a spectator sport. You cannot expect to acquire the
understanding you need to do well on an AP Exam by merely attending class
and listening to the teacher. It requires your active participation in the
learning process. You should ask questions such as "Why do we think this?"
and "What would happen if we did this?" and if you can't answer them, seek
the help of your physics teacher or other students.
Having the opportunity to answer these questions by exploring phenomena and
conducting experiments in the laboratory can often help you internalize the
concepts and make them more concrete. Some computer simulations that allow
you to set up hypothetical physical situations and observe the results of
changing various
quantities in the situations can also be helpful in developing conceptual
understanding.
When studying physics from a textbook, it is a good idea to have paper and
pencil with you. You could review by working the details of
solutions to example problems on your own. If you have completed the
problems assigned by your teacher for homework and are still not sure of
your understanding of the material, try some of the unassigned problems in
the book on the same topic.
Many students have the impression that physics is merely a list of formulas
to be memorized and recalled at the proper time. Of course, formulas and
equations are important in physics, but that is because physics is a science
that deals with principles that can be expressed quantitatively. The
equations are merely a way of expressing these principles. A feel for the
physical reality behind the equations will help you remember them better
than just trying to memorize a list.
You must study regularly. In a physics course, many topics are based on
preceding ones. Students who study regularly have the added advantage
of being able to
reinforce and enlarge on what they already know while tackling something
new.
The study of physics requires a high degree of concentration. Solutions to
physics problems must be carried out carefully and in a precise, orderly
manner. Be sure to draw a sketch of the problem in order to clarify what is
being asked.
If an error is made in a mathematical expression, it may be carried over to
the following parts of the problem. Solve your problems in pencil, neatly
and methodically. At every step of the analysis, be sure that you know your
reason for taking the step. Write your answers with the appropriate units.
PREPARING FOR THE AP PHYSICS
EXAM
Preparation for an exam is normally a cooperative venture between students
and teachers, you should assume total responsibility for studying and
learning the material presented in the course.
Preparation for an AP Exam through independent study is also possible. If
you exercise this option, the most important ingredient for success is
strong self-motivation, although it would be extremely useful to have access
to a teacher or tutor who can answer your questions and help you if you get
stuck.
The AP Physics examinations are given in May. To provide the most
information about differences in students' achievement in physics, the
examinations are designed so that students earn average scores of about 50%
of the maximum possible score; this applies to both the multiple-choice
section and the free-response section. Therefore, you may find AP
Examinations more difficult than most classroom tests. However, it is
possible for students who have studied most but not all of the topics in the
outline to obtain acceptable test scores.
Most AP students are accustomed to taking tests, both those prepared and
graded by their teachers and standardized exams. Virtually everyone knows
that regular study plus
reviews of major elements in the course constitute the best preparation for
tests. Effective study for examinations will vary somewhat among students.
For example, many students find it helpful to study in a group with other
students, while for others, group preparation may not work well. Some
students can "cram" for a test, memorizing large amounts of material in a
brief period of time just before the test. For others, cramming causes
cognitive overload and exam-day confusion.
If you want to master the skills and knowledge in your AP course, remember
that material that is reviewed periodically and skills that are reinforced
by practice are far more likely to remain with you than are those that are
hastily acquired and partially digested over a brief interval of time.
It's natural to be anxious when you are about to do something on which
others will judge your performance. The greatest anxiety moderator for most
people is knowledge; the more you know in advance about a course or an exam,
the better you can moderate your fears. Knowing about an exam means
understanding what kinds of questions you will be asked, how the exam will
be graded, how much time you'll have to respond, and so on. Knowing that you
are prepared in terms of the exam's content is probably the most calming
knowledge of all. Consistent study and review throughout the course is a
powerful reliever of excessive tension both for daily classroom learning and
for tests.
Directions
Be aware that not paying enough attention to directions on tests can
adversely affect your grade. On the AP Exams, phrases in the multiple-choice
sections like "All the following are . . . EXCEPT" or "Which of the
following does NOT . . ." contain critical words. If you don't pay attention
to them, you will not respond correctly to the questions.
There are also special directions in parts of the free-response questions.
For example, there may be directions that specify for you to explain what
principles to use in deriving an expression or directions that ask you to
express an answer using specific variables.
Time Limits
Make a quick estimate of the amount of time the various questions or
sections of a test will require, stay aware of the time available throughout
the test, and concentrate on questions they can respond to best. Move on to
the next question if you can't figure out the answer to the one you are
working on.
In the free-response questions, the number of points for the question is
specified after the question number. The number of points indicate the
weighting of the questions in the grading and are approximately equal to the
time that should be spent answering them for those who want to pace
themselves to finish in the given time limit.
Use all the time available to complete the exam. If you finish the exam with
time to spare, go back to questions you skipped or answers that you can
supplement. Check the directions again to be sure you've responded properly.
Answer Sheets
One of the common mistakes while filling the answers of the multiple-choice
section is getting responses out of sequence; for instance, marking an
answer for question 5 when the answer was intended for question 6. This can
happen easily when you skip a question, put a mark in your test book (not on
your answer sheet) when you do this.
Frequently check to be sure that the number of the question on your answer
sheet corresponds to the number of the question in your exam booklet.
Educated Guessing
For questions with five answer choices, one-fourth of a point is subtracted
for each wrong answer. This means that for answer sheets that are marked
completely at random, the average score would be expected to be zero.
Therefore, if you know absolutely nothing that helps you eliminate even one
of the multiple-choice options, you probably won't come out ahead by
guessing at an answer. But if you are fairly sure that even one of the
options is wrong, it may be worthwhile to answer the question. Of course, if
you can eliminate two or three options as probably incorrect, your chances
of gaining credit become even greater.
Eliminating Incorrect Responses
Multiple-choice questions are often very short problems with a choice of
answers that require a short calculation or derivation. However, you can use
the following tips to determine the answer more quickly or to eliminate
choices that are incorrect:
*
In some questions with numerical answers, the choices may differ by several
orders of magnitude so that the questions can be answered by estimation
rather than by exact calculation. You are encouraged to develop your skills
in making order-of-magnitude calculations to estimate such answers more
rapidly.
*
Recognizing that some choices are physically unreasonable or unlikely is
often a good way to narrow the possibilities for the correct answer. For
example, if you are asked to calculate the time it takes for a ball to fall
from the top of a house, you could immediately eliminate answers of 0.01
second or 100 seconds, since they are outside the range of physically likely
possibilities.
*
Some questions may ask you to derive an expression in symbolic form rather
than to calculate a numerical value. If you have trouble determining the
correct expression, you might try checking the units of each choice. Those
that do not have the units expected of the answer can be eliminated. For
example, if you are to determine an expression for a distance, then an
answer such as 2v/t, where v is speed and t is time, would have the
units of distance divided by time squared, and would therefore be
dimensionally incorrect.
*
For questions that give expressions in algebraic form, you might also look
at limiting cases; that is, at what would happen to the expressions if one
of the variables were very large or very small. If an expression predicts a
result that could not be reasonably expected or that is physically
impossible, then that choice can be eliminated as the correct answer. For
example, the expression 6 + 2t could not be correct for the speed of
a ball released from rest at time t equal to zero, since it does not
go to zero as t goes to zero.
Before beginning to solve the free-response questions consider reading all
the questions to determine which ones you feel best prepared to answer. Then
you can solve the questions in the order that will allow you to
perform your best.
You should show your work for each part of a question in the space provided
after that part, and if you need more space you should clearly indicate
where you are continuing your work. You will NOT receive credit if the
grader cannot tell which part of the question you are answering.
Show all your work. Partial credit is given for partial solutions to
problems. If you do not show your work, you may receive full credit for an
answer if it is correct, but you take a big risk because credit is often
based not just on the presence of the right answer but on
the correct use of appropriate steps leading to the right answer. If the
answer is not correct, you are not likely to receive credit for correct
thinking if the person scoring your examination does not see evidence of
this process on paper. If you do work that you think is incorrect, you
should simply put an "X" through it, instead of spending time erasing it
completely. Crossed-out work will not be graded, and credit may be lost for
incorrect work that is not crossed out.
Organize your answers as clearly and neatly as possible. Credit for your
answers depends on your demonstrating that you know which physical
principles can be applied in solving a particular problem, and an organized
answer in the appropriate answer space will better allow the grader to
determine whether you have demonstrated such knowledge. Also, show the steps
in your solution. If the grader cannot easily follow
your reasoning, you are less likely to receive credit for it.
The free-response questions on an AP Physics examination are usually divided
into parts such as (a), (b), (c), and (d), with each part calling for a
different response. Credit for each part is awarded independently, so you
should attempt to solve each part. For example, you may receive no credit
for your answer to part (a), but still receive full credit for parts (b),
(c), or (d). If the answer to a later part of a question depends on the
answer to an earlier part, you may still be able to receive full credit for
the later part, even if that earlier answer is wrong. The grade will depend
on your method of approach to the later part and on the consistency of your
answer with that of the earlier part.
You will sometimes be asked to justify your answer to a free-response
question. This indicates that the person scoring your answer is looking for
some analysis that will show how you derived your answer and prove that your
answer must be correct.
It is not necessary to simplify all numerical expressions or carry out all
numerical calculations. Pay attention to units for quantities that have
them. Keeping track of units as you do calculations can help you make sure
that your answers are expressed in terms of the proper units. You can lose
points if the units are wrong or are missing from your answers.
Do NOT write down a bunch of equations with the hope that the correct one
will be among them so you can get some partial credit. With the equation
sheets available, this approach is not likely to reward you with partial
credit, and you might lose points for giving extraneous or incorrect
information.
FORMAT and Content OF THE
EXAMINATIONS
The Physics B examination is three hours long and is divided equally in time
between a 70-question multiple-choice section and a free-response section.
The two sections are weighted equally, and a single grade is reported for
the B exam.
The free-response section will normally contain six to seven questions.
Typical examples of its format are six questions, each taking about 15
minutes, or four questions of about 15 minutes each and three shorter
questions of about 10 minutes each.
Content of the Examinations:
The percentages of each exam that are devoted to each major category are:
Newtonian Mechanics (35%)
Fluid Mechanics and Thermal Physics (15%)
Electricity and Magnetism (25%)
Waves and Optics (15%)
Atomic and Nuclear Physics (10%)