Physics II

Time and Date Stamps (logged): 12:49:22 05-21-2012 ｰｱ浹ｸ浤ｱｯｴ浤ｰ浤ｯｰｱ Physics II

University Physics (Phy 232, Phy 242) Test 3

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. **

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Name and Signature of Student _____________________________

Signed by Attendant, with Current Date and Time: ______________________

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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

Problem Number 2

A capacitor with capacitance 8 `microC/Volt is in series with a resistance of 8270000 Ohms and a 25 volt source. When the capacitor holds a charge of 33 `microC, approximately how long will it take it to increase its charge by 1%?

Problem Number 3

Point A is at potential -18.02 volts and point B is at potential 45.5 Volts. How much work is required to move a charge of 1.88 C from a point A to point B?

Problem Number 4

An electron (mass 9.11 * 10^-31 kg) passes to the East through a magnetic field of .0049 Tesla directed vertically downward, crossed with an electric field directed either North or South. The electron passes through undeflected at a velocity of 5.1 * 10^6 m/s. Is the electric field directed North or South, and what is the field strength? What force does the electron experience from each field?

Problem Number 5

A certain hypothetical atom contains 74 protons and 100 neutrons in its nucleus and has an atomic mass of 172.8 atomic mass units, or amu (an amu is approximately 1.66 * 10^-27 kg). How many protons and how many neutrons will it end up with if it undergoes an alpha decay? How many if it undergoes a beta decay? How many if it undergoes a gamma decay?

Problem Number 6

A coil consists of 49 circular loops of wire each of radius .27 meters. The coil is in a uniform magnetic field with strength .0079 Tesla. The coil is rotated in such a way that at t = 0 the field makes an angle of 75 degrees with a perpendicular to the plane of the loop, while at t = .01 sec the field makes an angle of -29.01 degrees with the same perpendicular. What is the average voltage induced around the coil?

Problem Number 7

A generator creates a potential difference of 3.1 volts when cranked at 1 revolution/sec, and the voltage is proportional to the cranking rate. If the generator has an internal resistance of 30 ohms, and is connected across a bulb whose resistance is 43 ohms, then if it is cranked at 2.1 revolutions / sec how much current will flow? How much power will be dissipated by the current? How much power will be dissipated in the bulb?

Problem Number 8

Find the force on a 6.9 `microCoulomb charge at ( 6.932 m, 5.205 m) due to a charge of 8.5 `microCoulombs at ( .981 m, 1.63 m). Find the PE change if the charges are moved .015 m closer together.

Problem Number 9

Use integration to find the torque exerted on a circular wire loop, lying in a horizontal plane and constrained to rotate about a horizontal axis through its center, by a vertical magnetic field B.

Problem Number 10

A square loop with area A and carrying current I lies initially stationary in a horizontal plane and is constrained to rotate about an axis parallel to two of its sides and passing through the center of the square. A vertical uniform magnetic field B permeates the region. If the loop has moment of inertia J, then what differential equation relates the angular position `theta of the loop to clock time?