PHY 184 Study Guide - Final Guide: G-Unit, Electronvolt, Rc Circuit

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9 Dec 2018

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2 pt two charged spheres are 8. 57 cm apart. They are moved closer to each other enough that the force on each of them increases 4. 30 times. How far apart are they now? (in cm: a(cid:13) 0. 445. The plate on the right is positively charged: a(cid:13) true. The potential energy of a positive charge moved from point a to point b will decrease: a(cid:13) true. B(cid:13) false: a, true, b, false, b, false, b, false, a, true. Choose true or false for each statement below about the uni- form electric eld shown above. A negative charge at point b is at a lower potential than point c: a(cid:13) true. The kinetic energy of a negative charge moved from point a to point b will increase: a(cid:13) true. The electrostatic force on a charge is greater at point a than at point b. A constant electric eld of magnitude e = 138 v/m points in the positive x-direction.

Related Questions

1.Two uncharged, conducting spheres, A and B, are held at rest oninsulating stands and are in contact. A positively charged rod isbrought near sphere A. While the rod is in place, the two spheresare separated. How will the spheres be charged, if at all, afterthey are separated?
Sphere A Sphere B
(a) positive positive
(b) positive negative
(c) negative positive
(d) negative negative
(e) zero zero

2. A charged conductor is brought near an uncharged insulator.Which one of the following statements is true?
(a) Both objects will repel each other.
(b) Both objects will attract each other.
(c) Neither object exerts an electrical force on the other.
(d) The objects will repel each other only if the conductor has anegative charge.
(e) The objects will attract each other only if the conductor has apositive charge.

3. An electron is moved from point A, where the electric potentialis VA = â240 V, to point B, where the electric potential is VB =â360 V. What is the change in the electric
potential energy?
(a) 1.92Ã10â17 J (b) 2.04Ã10â17 J (c) 5.75Ã10â17 J (d) 8.98Ã10â17 J(e) 1.05Ã10â16 J

4. A -2q charge is located a distance d to the right of a +4qcharge, along the x
axis. At which point (or points) along the axis does the electricfield go to zero? To
solve this problem, consider an observer at point P, which is anarbitrary distance x from the +4q charge. Find the value (orvalues) for x (in terms of the separation distance d) where thetotal electric field vanishes.
(a) The electric field is never zero in the vicinity of thesecharges.
(b) The electric field is zero at x = -0.328d.
(c) The electric field is zero at x = +4.22d.
(d) The electric field is zero at both x = -2.26d and x =+2.26d.
(e) The electric field is zero at x = +3.41d.

5. point A is a distance L away from a point charge Q. Point B is adistance 4L away from Q. What is the ratio of the electrostaticpotential at B to that at A, i.e., what is VB/VA?
(a) 1/16
(b) 1/9
(c) 1/4
(d) 1/3
(e) can not be determined without specifying Q and L

6. Which one of the following statements best explains why it ispossible to define an electric potential
in a region of space that contains an electric field?
(a) Work must be done to bring two positive charges closertogether.
(b) Like charges repel one another and unlike charges attract oneanother.
(c) A positive charge will gain kinetic energy as it approaches anegative charge.
(d) The work required to bring two charges together is independentof the path taken.
(e) A negative charge will gain kinetic energy as it moves awayfrom another negative charge.

Two small spheres of mass m and carrying absolute charge qare
suspended by massless threads of length L, as shown. Thedistance
between the anchor points of the threads is equal to d . Atequilibrium,
the two spheres lie in the same horizontal plane, and the threadseach
make an angle ? with the vertical.
1. (1 pt) Assuming the figure is correct and the charges arerepelled from
each other, choose the best answer below:
(a) Both spheres are positively charged
(b) Both spheres are negatively charged
(c) One sphere is negative and one is positive
(d) Both (a) and (b) are possible
(e) None of the above are possible
2. (2 pts) Draw a clear free-body diagram for the leftsphere.
3. (1 pt) What is the horizontal distance between the (centers ofthe) spheres, at equilibrium, in
terms of L, d and/or ? ?
4) (3 pts) What is the magnitude and direction of the electrostaticforce on the left sphere in
terms of m, g, and/or ? ?
5) (3 pts) What is the value of q in ?C, if d = 30 cm, L = 10 cm, ?= 30Â°, take g = 10 m/s2
and k = 9â¢109 (N m2/C2), and these are ping-pong balls of mass m =2.7 grams?

crimsonbadger665

1) A dipole with dipole moment 1.5 nC*m is oriented at 30 degreesto an electric field, 4.0*10^6 N/C. (a) What is the torque on thedipole? (b) How much work is required to rotate the dipole until itis parallel to the field (hint: think about work-energyrelationship)?

(2) Two parallel-plate capacitors with different plate separationbut the same capacitance are connected in series to a battery. Bothcapacitors are filled with air. The quantity that is NOT the samefor both capacitors when they are fully charged is (pleaseexplain):
(A) potential difference
(B) stored energy
(C) electric field between the plates
(D) charge on the positive plate
(E) dielectric constant

(3) 20 loops of wire with a radius of 7.5 cm rotates about adiameter in a uniform magnetic field of 1.6 T. To produce a maximumemf of 20.0 V, it should rotate at:
(A) 0
(B) 2.7 rad/s
(C) 5.6 rad/s
(D) 35 rad/s
(E) 71 rad/s

PHY 184 Study Guide - Final Guide: G-Unit, Electronvolt, Rc Circuit

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