PHY 242 Laboratory for 9/23/99

Exam I will take place during the lab period on Thursday, Sept. 23. You will have the full three hours, but most finish within two hours. The exam will consist of 6 to 8 problems and cover Chapters 22 through 27. Wednesday's class will be a question and answer session for the exam. Catch up on the homework problems and come prepared with questions!

Below are a few sample problems from a previous exam (1992). You are responsible for all material covered in lecture and homework assignments. DO NOT ASSUME that a subject not covered in the sample exam below will not show up on Thursday's exam!

During the exam, you will be provided with an equation sheet. You will be allowed to use only the equations on the sheet, or others that you derive from those on the sheet. I would suggest that you create your own equation sheet from the equations in the summary at the end of each chapter and use only that when trying the problems below. Resist the temptation to simply look for a similar problem in the text or notes(the standard "get the homework done" technique). That will better prepare you for the exam. If you can't solve the problems, come see me. And don't wait until Wednesday night!!

The following site provides some additional practice:

more exam practice

Sample Physics 242 Exam I

1. a) Find the total force acting on the charge at the top of the 3-4-5 triangle shown.
   b) What is the electrostatic potential energy of the -2q charge?

   

2. Set up the integral necessary to find the electric field a distance d along the bisector of a rectangular plate 2a by 2b with uniform charge density s. (Be sure to include limits and variable substitutions.)

   

3. A long non-conducting hollow cylinder of inner radius a and outer radius b has uniform volume charge density r . Find the electric field for r < a and for a < r < b.

   

4. Below are two conducting plates connected to a 10 V battery as shown. a) Sketch and label the electric field lines. Sketch the equipotential lines corresponding to every 2 V.
   b) If an electron escapes from the negative plate, what is its speed when it reaches the opposite plate? Sketch a possible path for this electron.

   

5. A 3 µF and a 6 µF capacitor are connected in series with a 10 V battery. What is the charge on and voltage across each capacitor?
6. a) Label currents in each of the branches of the circuit below and write out the equations necessary to solve for them.