MC Questions
Gauss's Law
Electric Flux - Diagrams
Electric Potential and Electric Potential Energy
(Kinda) Fun
100
Two conducting spheres of different radii are charged with the same charge -Q. What will happen to the charge if the spheres are connected with a conducting wire? (A) Negative charge flows from the large sphere to the smaller sphere until the electric field at the surface of each sphere is the same (B) Negative charge flows from the smaller sphere to the larger sphere until the electric field at the surface of each sphere is the same (C) Negative charge flows from the large sphere to the smaller sphere until the electric potential at the surface of each sphere is the same (D) Negative charge flows from the smaller sphere to the larger sphere the electric potential at the surface of each sphere is the same (E) There is no charge flow between the spheres
D
100
How would one orient a planar surface of area A in a uniform electric field of magnitude 𝐸0 to obtain (a) the maximum flux and (b) the minimum flux through the area?
Max: 0 degrees
Min: 90 degrees
100
In the figure, is Φ1 larger than, smaller than, or equal to Φ2?
Φ1 > Φ2
Φ1 < Φ2
Φ1 = Φ2
3
100
Will a negative charge, initially at rest, move toward higher or lower potential?
Higher
100
What is only one letter that doesn’t appear in any U.S. state name?
Q
200
Two charges +Q and –Q are placed at the corners of equilateral triangle with a side r. What is the net electric potential at point C? (A) 0 (B) √3𝑘𝑄 / 𝑟 (C) 𝑘𝑄 / 𝑟 (D) √5𝑘𝑄 / 𝑟 (E) 2𝑘𝑄
D
200
If a rectangular area is rotated in a uniform electric field from the position where the maximum electric flux goes through it to an orientation where only one fourth the flux goes through it, what is the angle of rotation?
75.52 degrees
200
The square and circle in the figure are in the same uniform field. The diameter of the circle equals the edge length of the square. Is Φsquare larger than, smaller than, or equal to Φcircle?
Φsquare > Φcircle
Φsquare < Φcircle
Φsquare = Φcircle
1
200
A negative test charge is to be placed in the electric field shown. At which position, A, B, or C, the test charge has the highest potential energy?
(a) A
(b) B
(c) C
(d) Not sure, it depends on the field strength at each location.
B
200
In a room of 23 people, what is the chance of two people having the same birthday?
50%
300
Two parallel conducting plates are connected to a battery with a constant voltage. The magnitude of the electric field between the plates is 1200 N/C. If the voltage is halved and the distance between the plates is tripled from the original distance. The magnitude of the new electric field is: (A) 800 N/C (B) 600 N/C (C) 400 N/C (D) 500 N/C (E) 200 N/C
E
300
Positive charge Q is placed on a conducting spherical shell with inner radius R1 and outer radius R2 . A particle with charge q is placed at the center of the cavity. The magnitude of the electric field at a point in the cavity, a distance r from the center, is:
a) zero
b) Q / 4πε0R^2
c) q / 4πε0r^2
d) q+Q / 4πε0r^2
e) q+Q / 4πε0(R ^2 −r ^2)
c
300
The sphere and ellipsoid in the figure surround equal charges. Four students are discussing the situation.
Student 1: The fluxes through A and B are equal because the average radius is the same.
Student 2: I agree that the fluxes are equal, but that's because they enclose equal charges.
Student 3: The electric field is not perpendicular to the surface for B, and that makes the flux through B less than the flux through A.
Student 4: I don't think that Gauss's law even applies to a situation like B, so we can't compare the fluxes through A and B.
Who do you agree with?
Student 1
Student 2
Student 3
Student 4
2
300
What is the strength of the electric field in a region where the electric potential is constant?
The electric field strength is zero because electric potential differences are directly related to the field strength.
300
How many hearts does an octopus have?
3
400
Which of the following statements is true about the charged conducting sphere? (Hint: There are two answers). (A) The electric field is maximum at the center of the sphere (B) The electric potential is minimum at the center of the sphere (C) The electric field is zero inside the sphere (D) The electric potential everywhere inside the sphere and at the surface is the same
C, D
400
If the particle can be moved to any point within the cube, what maximum value can the flux through one face approach?
a) 0
b) q/ε0
c) q/2ε0
d) q/4ε0
e) q/6ε0
f) q/8ε0
c
400
3
400
If the voltage between two points is zero, can a test charge be moved between them with zero net work being done? Can this necessarily be done without exerting a force?
Yes, no.
400
What is the average weight of a cloud?
1.1 million pounds
500
A parallel-plate capacitor is connected to a battery with a constant voltage. The capacitor becomes fully charged and stays connected. What happens to the energy stored in the capacitor if the separation is decreased? (A) Remains the same (B) Increased (C) Decreased (D) Zero (E) More information is required
B
500
Gauss's law could easily be used to solve for the electric field outside of all of the following charge distributions expect a
A) charged nonconducting sphere
B) long straight line of charge
C) long charged conducting cylinder
D) charged nonconducting cube
E) charged nonconducting plane
B
500
A small, metal sphere hangs by an insulating thread within the larger, hollow conducting sphere of the figure. A conducting wire extends from the small sphere through, but not touching, a small hole in the hollow sphere. A charged rod is used to transfer positive charge to the protruding wire. After the charged rod has touched the wire and been removed, are the following surfaces positive, negative, or not charged?
The small sphere.
Positive
Negative
Not charged
The inner surface of the hollow sphere.
Positive
Negative
Not charged
The outer surface of the hollow sphere.
Positive
Negative
Not charged
1, 2, 2
500
Can the potential of a nonuniformly charged sphere be the same as that of a point charge?
500
What is the value of gravity in San Diego?
9.75 m/s^2