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Physics II
Principles of Physics (Phy 122) Test_Set_4
Completely document your work and your reasoning.
You will be graded on your documentation, your reasoning, and the
correctness of your conclusions.
** Write clearly in dark pencil or ink, on one side of the paper
only. **
10-03-2001 20:36:41
Test should be printed using Internet Explorer. If
printed from different browser check to be sure test items have not been cut off. If
items are cut off then print in Landscape Mode (choose File, Print, click on Properties
and check the box next to Landscape, etc.).
Name and Signature of Student
_____________________________
Signed by Attendant, with Current Date and Time:
______________________
If picture ID has been matched with student and name as
given above, Attendant please sign here: _________
Instructions:
- Test is to be taken without reference to text or
outside notes.
- Graphing Calculator is allowed, as is blank paper or
testing center paper.
- No time limit but test is to be taken in one
sitting.
- Please place completed test in Dave Smith's folder,
OR mail to Dave Smith, Science and Engineering, Va. Highlands CC, Abingdon, Va.,
24212-0828 OR email copy of document to dsmith@vhcc.edu,
OR fax to 276-739-2590. Test must be returned by individual or agency supervising test. Test is not to be returned to student after it has been taken. Student may, if proctor deems it feasible, make and retain a copy of the test..
Directions for Student:
- Completely document your work.
- Numerical answers should be correct to 3 significant
figures. You may round off given numerical information to a precision consistent
with this standard.
- Undocumented and unjustified answers may be counted
wrong, and in the case of two-choice or limited-choice answers (e.g., true-false or
yes-no) will be counted wrong. Undocumented and unjustified answers, if wrong, never get
partial credit. So show your work and explain your reasoning.
- Due to a scanner malfunction and other errors some
test items may be hard to read, incomplete or even illegible. If this is judged by
the instructor to be the case you will not be penalized for these items, but if you
complete them and if they help your grade they will be counted. Therefore it is to
your advantage to attempt to complete them, if necessary sensibly filling in any
questionable parts.
- Please write on one side of paper only, and staple
test pages together.
Test Problems:
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Constants
Constants:
| k = 9*10^9 N m^2 / C^2 |
qE = 1.6 * 10^-19 C |
h = 6.63 * 10^-34 J s |
| energy of n=1 orbital in hydrogen atom: -13.6 eV |
k ' = 9 * 10^-7 T m / amp |
atomic mass unit: 1.66 * 10^-27 kg |
| electron mass: 9.11 * 10^-31 kg |
speed of light: 3 * 10^8 m/s |
Avogadro's Number: 6.023 * 10^-23 particles/mole |
| Gas Constant: R = 8.31 J / (mole K) |
proton mass: 1.6726 * 10^-27 kg |
neutron mass: 1.6749 * 10^-27 kg |
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Problem Number 1
A magnetic field of magnitude .1 Tesla passes through a square loop with side 6.5
meters, with the field perpendicular to the plane of the loop. The loop rotates at 7.1 Hz.
The loop is connected so that the voltage is across a resistance of .2 `Ohms.
What is the average power required to turn the loop, if we assume that power generation is
31% efficient? Ignore the effects of self-induction in the loop, but explain what
self-induction is and what effect it might have on your answer.
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Problem Number 2
A magnetic field of magnitude 2.2 Tesla passes through a square loop with side 9.4
meters, with the field at an angle of 2.2 degrees with a perpendicular to the plane of the
loop.
- If the loop is suddenly turned , in .01 seconds, to make an angle of .2 degrees,
then what average voltage will be produced?
- If the voltage is connected to a resistance of 8.8 `Ohms, then how much average
power is required? Ignore the effects of self-induction in the loop, but explain what
self-inductance is and what effect it might have on your answer.
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Problem Number 3
What is the power flux of light whose intensity is 5.6 watts/m ^ 2 through a
circular window with radius 2.6 meters, if the sunlight is perpendicular to the plane of
the window?
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Problem Number 4
Find the strength of the magnetic field due to a
straight current segment of length .039 m, at a distance of 7.2 meters from the segment,
provided that the vector from the segment to the point is perpendicular to the segment,
and that a current of 8.2 Amps flows in the segment.
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Problem Number 5
What is the flux of a magnetic field of magnitude 7.4 Tesla through a circular
loop with radius 6.7 meters, if the field makes an angle of 48.4 degrees with a perpendicular
to the plane of the loop?
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Problem Number 6
A particle carrying charge 8 `microCoulombs moves at constant velocity through a
combined electric and magnetic field. Both fields are perpendicular to one another and to
the direction of motion of the charge, and are oriented so that the forces exerted by the
two fields are in opposite directions. The electric field has strength E = 52000 N / C and
the magnetic field has strength B = .02 Tesla.
- Show that the charge passes through the field without a change in direction provided its
velocity is v = E / B.
- Show that the same is the case if the charge is 15 `microCoulombs, and explain why the
change in charge had no effect on the result.