Physics II

Time and Date Stamps (logged): 05:27:10 12-05-2008 ｯｴ浤ｶ涓ｯｰｱ浣ｴ浤ｯｯｷ 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 20:36:46

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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:

. . . . . . . . . . . . . . . .

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

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.

Problem Number 2

What is the power flux of light whose intensity is .2 watts/m ^ 2 through a square window with side 10 meters, if the sunlight makes an angle of 90 degrees with a 'normal' line perpendicular to the plane of the window?

Problem Number 3

What will be the force on an electron (mass approximately 9 * 10^-31 kg, charge -1.6 * 10^-19 C) as it moves in the horizontal direction at velocity 8.4 * 10^6 m/s within a uniform magnetic field of .0035 Tesla directed vertically upward? What will be the radius of curvature of its path? Describe its path. What would be the radius of curvature for a proton (mass approximately 1.6 * 10^-27 kg) moving at the same velocity? Describe specifically how its path would differ from that of the electron.

Problem Number 4

What is the electrostatic flux of a field of magnitude 3.3 N/C through a circular region with radius 7.2 meters, if the field makes an angle of 80 degrees with a perpendicular to the plane of the region?

Problem Number 5

A particle carrying charge 5 `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 = 24000 N / C and the magnetic field has strength B = .49 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 14 `microCoulombs, and explain why the change in charge had no effect on the result.

Problem Number 6

Find the magnitude of the magnetic field due to a straight current segment of length .039 m, at a distance of 7.8 meters from the segment, given that the vector from the midpoint of the segment to the point makes at angle 12 degrees with the segment, and that a current of 3.3 Amps flows in the segment.