Common Exam 1 Exam grades posted High 18Low 5Average 12 Graded out of 16 problems (so equivalently 2 extra credits) For Exam 1, If answer on Scantron correct, problem counted as correct, but… Check your concerning announcements about update to course web page and new policies for common exams One problem had two correct answers… either answer is counted as correct. You must show how you got your answer on this set of exam sheets, including using the back if necessary. The professors may assume that answers with no work are guesses and indicate no understanding. Instructions on Exam 1:

NEW POLICY (1)only calculators will be allowed in exams. No cell phones, ipads, ipods, ear phones, etc. will be allowed. Any device that can communicate with another (pagers, smart phones, etc) will not be allowed. If you do not own a calculator, you will need to purchase one before the next exam. (2) Starting with common exam #2, some problems will REQUIRE you to work out the solutions in detail. For these problems (which will be indicated on the exams), the problem will be marked as wrong if your work does not justify your answer. THis rule applies even if you have the correct answer on the scantron score sheet.

Electric potential analogous to GRAVITATIONAL potential if we treat +q similar to mass m Positive charges “fall” downhill, following electric field….

Will a positive charge naturally move (“fall”) from point B to A? What is required to have positive charge move “uphill” from A to B? In what direction do negative charges “fall”?

Positive charges move to LOWER potential. Negative charges move to HIGHER potential

Clicker Question #1 Which of the following movements of charge represent the largest change in electric potential? A BC D E

Clicker Question #2 Which of the following charge arrangements requires the MOST amount of energy to assemble? A B C D E

Electric field lines are PERPENDICULAR to surfaces of CONSTANT potential.

Surface of conductor is CONSTANT potential surface

Clicker Question #3 What is the correct order for INCREASING magnitude of the electric field from this electric potential map? A) A, B, C B) B, C, A C) C, A, B D) A, C, B E) M, I, C, K, E, Y, M, O, U, S, E A B C

Clicker Question #4 Which of the following conditions is IMPOSSIBLE A) A region where E=0 requires the voltage in that region to also be zero. B) A region where V=0 requires that the electric field also be zero. C) The Voltage versus x position graph below on left. D) The Voltage versus x position graph below on right. E) All are possible.

Clicker Question #5 Which of the following statements is false? A) The electric field inside of the central sphere is zero. B) The charge on the INSIDE surface of the shell is -Q C) The charge on the OUTSIDE surface of the shell is Q D) The electric field in between the two conductors is measured relative to center of center sphere. E) The electric field in between the two conductors can not be easily calculated between the two conductors using Gauss’s law.