Physics II

Time and Date Stamps (logged): 17:12:20 06-10-2020 ｰｶ涓ｱ浤ｯｯｵ涓ｯ浤ｯｱｯ Physics II

Principles of Physics (Phy 122) Final Exam

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 20:40:26

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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

Suppose that a closed system with a constant number of moles of an ideal gas and a constant temperature has a pressure of 111.9 kN/m^2 when the volume of the system is .67 m^3. What is the pressure when the volume is increased to 1.34 m^3?

Problem Number 2

A capacitor holds charge 6 `microC/Volt. It is in series with a resistance of 4230000 Ohms and a 41 volt source. When the capacitor holds a charge of 51 `microC, approximately how long will it take it to increase its charge by 1%?

Problem Number 3

How much energy will an electron in orbit about a hydrogen atom lose in a transition from orbit # 3 to orbit # 5, where orbits are counted from the closest outward? If this lost energy is carried away by a photon, what will be its wavelength?

Problem Number 4

Problem Number 5

What is the average force associated with 4300 * 10^6 particles, each of mass 6.884132E-08 Kg, colliding elastically with a wall at a velocity of 103.9 m/s, with directions randomly distributed in 3 dimensions? Assume that the wall is one of the walls of a rectangular 'box', separated by 1 meters from the wall parallel to it.

Problem Number 6 122)

A longitudinal wave is one in which the particles move parallel to the direction of motion. In this case, a sine wave will move each particle from its equilibrium position as dictated by a sine function.

If a longitudinal sine wave travels along the x axis at 90 m/s with a wavelength of .4 m and amplitude of particle motion equal to .23 meters, then what is the position vs. time function of a particle whose equilibrium position is at x = 4.3 meters? Assume that at time t = 0 the x = 0 particle is at its equilibrium position and moving in the positive direction.

Problem Number 7

Two uniform wires having circular cross-sections, both with the same length and made of identical material, are both maintained at the same potential difference and the same temperature. The first wire has diameter 3.6 mm, while the second has diameter 4.4 mm. If the current in the first wire is .9 amps, then what is the current in the second wire?

Problem Number 8

Find the magnitude of the magnetic field due to a straight current segment of length .033 m, at a distance of 3.7 meters from the segment, given that the vector from the midpoint of the segment to the point makes at angle 65 degrees with the segment, and that a current of 9.9 Amps flows in the segment.

Problem Number 9

If water flows at 4 m/s through a tube whose radius is .13 m, then what will be the flow speed if the tube narrows to radius 4.333333E-02 m?

Problem Number 10

What are the x and y components of the electric force on a charge of 6 `microC at the point (-19.01 m, 7 m), due to a charge of 1 `microC at (-17.01 m, 3 m)?

Problem Number 11

An alpha particle consists of two protons and two neutrons. The neutrons are slightly more massive than the protons, but the average mass of all the particles is reasonably close to 1.6 * 10^-27 kg. The fundamental charge is 1.6 * 10^-19 Coulomb. If a beam of alpha particles moving at 2.5 * 10^6 m/s enters a magnetic field of .0029 Tesla, with the velocity and field perpendicular to one another, what will be the radius of the circular path of the beam in the magnetic field?

Problem Number 12

Which isotopes of which elements in the table below might possibly decay into which isotopes of which other elements by means of alpha emission?

Which isotopes of which elements in the table below might possibly decay into which isotopes of which other elements by means of beta decay consisting of emission of a negative electron?

Which isotopes of which elements in the table below might possibly decay into which isotopes of which other elements by means of beta decay consisting of electron capture?

From the table below, determine at least one series of alpha and beta decays that will lead from uranium-238 to lead-206. Specify the two isotopes involved in each decay, and tell whether the process is an alpha or a beta decay.

Nuclear Composition of Selected Heavy Nuclei

particle or atom	lead	bismuth	polonium	radon	radium	thorium	palladium	uranium
atomic number	82	83	84	86	88	90	91	92
nucleons	214	214	218	222	226	230	234	238
nucleons	210	210	214			234		235
nucleons	206	209	210					234

Problem Number 13

If the distance between consecutive peaks of a wave is 3 meters, and if 20 peaks pass in a second, then how fast is the wave moving?

Problem Number 14

The potential gradient dV/dx in a circuit (or elsewhere) determines the force on a given charge. This can be understood through the example of the following problem:

If a potential gradient of 16 volts/meter exists between two points over a displacement of .67 meters, what is the voltage between the points, and how much work will be done on a charge of 27 Coulombs as it moves between these points?
From the work done and the displacement, determine the average force on the charge.
Repeat these calculations for the same potential gradient with a displacement of 2.4 meters.

From your results, state whether it is the potential gradient or the charge which determines the force.

From potential gradient dV/dx and displacement ds, find an expression for the work done on a charge q as it moves through this displacement, and use this expression to find an expression for the force on the charge. Give the resulting force for a charge of 88 Coulombs within a potential gradient of `potGrad2 volts/meter.

Problem Number 15

A magnetic field of magnitude 6.4 Tesla passes through a square loop with side 3.1 meters, with the field perpendicular to the plane of the loop. The loop rotates at 5.5 Hz. What is the average magnitude of the voltage produced?