Monday, May 12, 2008
Afternoon

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 examination.

The free-response section will normally contain from six to eight 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 ten minutes each.

The Physics C examination consists of two parts, each one and one-half hours long. One part covers mechanics; the other part, electricity and magnetism. A student may take either or both parts, and a separate grade is reported for each. In addition, each part is divided equally in time between a 35-question multiple-choice section and a free-response section; the two sections are weighted equally in the determination of each grade. Each of the two free-response sections contains three questions. A student is expected to spend about 15 minutes answering each of these questions.

The multiple-choice sections of both examinations emphasize the breadth of the students' knowledge and understanding of the basic principles of physics. The free-response sections emphasize the application of these principles in greater depth in solving more extended problems, for example:

• determine directions of vectors or paths of particles
• draw or interpret diagrams
• interpret or express physical relationships in graphical form
• account for observed phenomena
• interpret experimental data, including their limitations and uncertainties
• construct and use conceptual models and explain their limitations
• explain steps taken to arrive at a result or to predict future physical behavior
• manipulate equations that describe physical relationships
• obtain reasonable estimates
• solve problems that require the determination of physical quantities in either numerical or symbolic form and that may require the application of single or multiple concepts.

Laboratory-related questions may ask students to:
 

• design experiments, including identifying equipment needed and describing how it is to be used; drawing diagrams or providing descriptions of experimental setups; or describing procedures to be used, including controls and measurements to be taken
• analyze data, including displaying data in graphical or tabular form, fitting lines and curves to data points in graphs, performing calculations with data, or making extrapolations and interpolations from data
• analyze errors, including identifying sources of error and how they propagate, estimating magnitude and direction of errors, determining significant digits, or identifying ways to reduce error
• communicate results, including drawing inferences and conclusions from experimental data, suggesting ways to improve experiments, or proposing questions for further study

In grading the free-response sections, credit for answers depends on the quality of the solutions and explanations shown, so students should show their work. If students make a mistake they may cross it out or erase it. Crossed-out work will not be graded, and credit may be lost for incorrect work that is not crossed out.

The examinations are designed to provide the maximum information about differences in students' achievement in physics. Therefore, it is intended that the average scores be about 50 percent of the maximum possible scores for each of the multiple-choice and free-response sections. Students should be aware that they may find these examinations more difficult than most classroom examinations. However, it is possible for students who have studied most but not all topics in the outlines to obtain acceptable grades.

The use of the rulers or straight edges is permitted on the examination is to facilitate the sketching of graphs or diagrams that might be required in the free-response sections.

Calculators/Reference Tables

I. Calculators are not permitted on the multiple-choice section of either AP Physics exam.
The purpose of the multiple-choice sections is to assess the breadth of students' knowledge and understanding of the basic concepts of physics. The multiple-choice questions emphasize conceptual understanding and qualitative applications. However, many physical definitions and principles are quantitative by nature and can therefore be expressed as equations. The knowledge of these basic definitions and principles, expressed as equations, is a part of the content of physics that should be learned by physics students and will continue to be assessed in the multiple-choice sections. However, any numeric calculations using these equations required in the multiple-choice sections will be kept simple. Also, in some questions the answer choices differ by several orders of magnitude so that the questions can be answered by estimation. Students should be encouraged to develop their skills not only in estimating answers but also in recognizing answers that are physically unreasonable or unlikely.

II. Calculators are allowed on the free-response section of both examinations.
Any programmable or graphing calculator may be used except those with typewriter-style (QWERTY) keyboards. Students are not required to erase their calculator memories before and after the examination. Calculators may not be shared with other students.

The free-response sections emphasize solving in-depth problems where knowledge of which principles to apply and how to apply them is the most important aspect of the solution to these problems. Regardless of the type of calculator allowed, the examinations have been and will continue to be designed and graded to minimize the necessity of doing lengthy calculations. Except for some fundamental constants, most numerical values are selected so that calculations with them are simple and can be done quickly. When free-response problems involve calculations, most of the points awarded in the grading of the solution are given for setting up the solution correctly rather than for actually carrying out the computation.

III. A Table of Information is provided with both sections of both exams.
For both the Physics B and Physics C examinations, the Table of Information is printed near the front cover of the multiple-choice section and on the green insert provided with the free-response section. The tables are identical for both examinations except for one convention as noted.

IV. Equation Tables containing commonly used physics equations are provided with each exam for use on the free-response section.
The equation tables for each examination are printed only on the green insert provided with the free-response section. The lists of equations may NOT be used when taking the multiple-choice sections. In general, the equations for each year's exam will be printed and distributed with the Course Description at least a year in advance so that students can get used to using them throughout the year. However, since the equations will be provided with the exams, students are NOT allowed to bring their own copies to the examination room.

The equations in the tables express the relationships that are encountered most frequently in AP Physics Courses and Examinations. However, the tables do not include all equations that might possibly be used. For example, they do not include many equations that can be derived by combining other other equations in the tables. Students are responsible for understanding the physical principles that underlie each equation and for knowing the conditions for which each equation is applicable.

The equation tables are grouped in sections according to the major content category in which they appear. Within each section, the symbols used for the variables in that section are defined. However, in some cases the same symbol is used to represent different quantities in different tables. It should be noted that there is no uniform convention among textbooks for the symbols used in writing equations. The equation tables follow many common conventions, but in some cases consistency was sacrificed for the sake of clarity.

One of the purposes of providing these equations is to make the free-response sections equitable for those students who do not have access to equations stored in their calculators. The availability of these equations means that in the scoring of the free-response sections, little or no credit will be awarded for simply writing down correct equations or for ambiguous answers unsupported by explanations or logical development.

Summing Up
The purpose of minimizing numerical calculations in both sections of the examinations and providing equations with the free-response section is to place greater emphasis on the understanding and application of fundamental physical principles and concepts. For solving problems, a sophisticated programmable or graphing calculator, or the availability of stored equations, is no substitute for a thorough grasp of the physics involved.