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Physics 242
General Physics II

Dr. Tom Sandin
Professor Emeritus

Office: Marteena 308B

Office Hours: MWR 12-3 or
by appointment

Tel: (336)285-2124
Fax: (336)256-0815
sandint@ncat.edu

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  • This semester's syllabus
  • Block 1, Part 2

  • Block 1, Part 2 Notes
  • Block 1, Part 2 Objectives
  • Block 1, Part 2 Drill Set
  • Block 1, Part 1

  • Block 1, Part 1 Notes
  • Block 1, Part 1 Objectives
  • Block 1, Part 1 Drill Set
  • DIRECTIONS TUTORIAL

    1. A positive point charge is directly above another positive point charge.

    +

    +

    Both are in the plane of the screen.
    What direction is the force exerted on the upper positive charge by the lower positive charge?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE
    (You should understand why the direction is the same if both charges were negative.)

    2. A positive point charge is directly above a negative point charge.

    +

    -

    Both are in the plane of the screen.
    What direction is the force exerted on the upper positive charge by the lower negative charge?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE
    (You should understand why the direction is the same if their charges were exchanged.)

    3. An external electric field exerts a force toward the top of the screen on an electron. What is the direction of that electric field?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    4. An external electric field directed to the left exerts a force on a proton. What is the direction of that force?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    5. A positive charge is directly in front of you in the plane of the screen. Point P is on a line between the charge and you. (The line is perpendicular to the screen.) At point P, what is the direction of the electric field set up by that positive charge?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    6. A different point P is to the left of a negative charge.   P·                -
    Both are in the plane of the screen.
    At that different point P, what is the direction of the electric field set up by that negative charge?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    7. A positive point charge is directly above a negative point charge.

    +

    -

    Both have the same absolute value and both are in the plane of the screen.
    What direction is their electric dipole moment?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    8. An electric dipole is in a uniform external electric field.
    The direction of its electric dipole moment is 25° N of E.
    The direction of the external electric field is opposite (25° S of W).
    What is the angle phi used to calculate torque and electric potential energy?
    zero 25° 90° 180°

    9. In Question 8 above, what direction should you choose for the electric potential energy?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    10. In Question 8 above, what direction should you choose for the torque?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    11. Another electric dipole is in another uniform external electric field.
    The direction of its electric dipole moment is into the screen.
    The direction of the external electric field is to the right.
    Now what is the angle phi used to calculate torque and electric potential energy?
    zero 90° 180°

    12. In Question 11 above, what direction should you choose for the torque?
    left right toward the top toward the bottom into the screen out of the screen UNDETERMINED NONE

    Strongly recommended by PHYS 242 students to learn a right-hand rule:
    Try these movies first.
    If the movies don't run on your computer, use these animated GIFs.

    Counter reset to zero 8/16/16.