Physics II Exam 1 Concepts
A solid conductor carries a net positive charge Q. There is a hollow cavity within the conductor, at whose center is a negative point charge −q (figure (Figure 1)). a) What is the charge on the outer surface of the conductor? Express your answer in terms of the variables Q and q. b) What is the charge on the inner surface of the conductor's cavity? Express your answer in terms of the variables QQ and qq.
Qout= -q+Q Qin= q
Can electric field lines intersect in free space? a. No b. Yes, but only at the midpoint between a positive and a negative charge c. Yes, but only at the midpoint between two equal like charges d. Yes, but only at the centroid of an equilateral triangle with like charges at each corner.
a
For a proton moving in the direction of the electric field a. its potential energy decreases and its electric potential decreases. b. its potential energy increases and its electric potential increases. c. its potential energy decreases and its electric potential increases. d. its potential energy increases and its electric potential decreases. f. both its potential energy and it electric potential remain constant.
a
A negative charge is moved from point A to point B along an equipotential surface. Which of the following statements is true for this case? a. No work is required to move the negative charge from point A to point B. b. Work is both required and performed in moving the negative charge from point A to point B. c. Not enough information is given to make a statement about the work involved. d. The negative charge performs work in moving from point A to point B. e. Work is required to move the negative charge from point A to point B.
a
A positive charge is moved from point A to point B along an equipotential surface. How much work is performed or required in moving the charge? a. No work is performed or required in moving the positive charge from point A to point B. b. Work is performed in moving the positive charge from point A to point B. c. Work is both performed and required in moving the charge from point A to point B. d. Work is required in moving the positive charge from point A to point B.
a
A solid block of metal in electrostatic equilibrium is placed in a uniform electric field. Give a statement concerning the electric field in the block's interior. a. There is no electric field in the block's interior b. The interior field points in a direction that is at right angles to the exterior field c. The interior points in a direction that is parallel to the exterior field. d. The interior field points in a direction opposite to the exterior field e. Not enough information is given to make a statement concerning the electric field on the block's interior.
a
An atom has more electrons than protons. The atom is a. a negative ion b. a positive ion c. an insulator d. a conductor e. a semiconductor.
a
For an electron moving in a direction opposite to the electric field a. its potential energy decreases and its electric potential increases b. its potential energy decreases and its electric potential decreases c. both its potential energy and it electric potential remain constant d. its potential energy increases and its electric potential decreases. e. its potential energy increases and its electric potential increases.
a
Four point charges of equal magnitude but with varying signs are arranged on three of the corners and at the center of the square of side d as shown in Fig. 21-3. Which of the arrows shown represents the net force acting on the center charge? a. A b. B c. C d. D e. none of the above
a
Four point charges of equal magnitudes but with varying signs are arranged on three of the corners and at the center of the square of side d as shown in Fig. 21-2. Which of the arrows shown represents the net force acting on the center charge? a. A b. B c. C d. D e. none of the above
a
Four point charges of varying magnitude and sign are arranged on the corners of the square of side d as shown in Fig. 21-6. Which of the arrows shown represents the net force acting on the point charge with a charge +Q? a. A b. B c. C d. D e. none of the above
a
If a charge is located at the center of a spherical volume and the electric flux through the surface of the sphere is Φ0Φ0, what is the flux through the surface if the radius of the sphere doubles? a. Φ0 b. 5Φ0 c. 0.125Φ0 d. 0.500Φ0 e. 8Φ0
a
If a negative charge is initially at rest in an electric field, will it move toward a region of higher potential or lower potential? a. it will move toward a region of higher potential b. it will move toward a region of lower potential c. it will stay at rest
a
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 half the flux goes through it, what has been the angle of rotation? a. 60° b. 90° c. 45° d. 30° e. 26.6°
a
If an atom has become a positive ion, it has a. lost an electron or electrons b. lost a proton or protons c. gained a proton or protons d. gained an electron or electrons e. gained a proton and an electron.
a
If two uncharged objects are rubbed together and one of them acquires a positive charge then the other one a. acquires a negative charge b. may or may not acquire a negative charge c. remains the same d. also acquires a positive charge e. may or may not acquire a positive charge.
a
Is it possible to have a zero electric field value between two positive charges along the line joining the two charges? a. Yes, regardless of the magnitude of the two charges b. Yes, if the two charges are equal in magnitude c. No, a zero electric field cannot exist between the two charges d. cannot be determined without knowing the separation between the two charges e. cannot be determined without knowing the magnitude of the charges
a
Materials in which the electrons are bound very tightly to the nuclei are referred to as a.insulators b. semiconductors c. superconductors d. polar e. conductors.
a
The energy acquired by a particle carrying a charge equal to that on the electron as a result of moving through a potential difference of one volt is referred to as a. an electron-volt. b. a proton-volt. c. a coulomb. d. a joule. e. a neutron-volt.
a
The work done in moving a positive charge by an electric field does not depend on the path chosen in moving the charge in that field. Based on the statement, what kind of force field is the electrostatic field? a. conservative b. quantized c. discrete d. polarized e. nonconservative
a
Two charges Q1 and Q2 of equal magnitudes and opposite signs are positioned as shown in Fig. 21-7. Which of the shown arrows represents correctly the electric field at point P? a. A b. B c. C d. D e. The field is equal to zero at point P.
a
What can you say about the flux through a closed surface that encloses an electric dipole? a. The net flux will be zero b. The net flux will be positive c. The net flux will be negative.
a
Which of the arrows shown in Fig. 21-10 represents the correct direction of the electric field between the two metal plates? a. A b. B c. C d. D e. none of the above
a
A positive charge moves in the direction of an electric field. Which of the following statements are true? Check all that apply. a. The potential energy associated with the charge decreases. b. The electric field does positive work on the charge. c. The electric field does not do any work on the charge. d. The potential energy associated with the charge increases. e. The electric field does negative work on the charge.
a, b
Which of the following statements are true? Check all that apply. a. In a uniform electric field, the field lines are straight, parallel, and uniformly spaced b. The electric force acting on a point charge is proportional to the magnitude of the point charge c. Electric field lines near positive point charges radiate outward d. The electric field created by a point charge is constant throughout space e. Electric field lines near negative point charges circle clockwise.
a, b, c
Which of the following statements are true? Check all that apply. a. Two negative charges repel each other b. A positive charge and a negative charge attract each other c. Electric charge is conserved d. Two positive charges attract each other e. Electric charge is quantized f. A neutral object contains no charge.
a, b, c, e
Which of the following statements are true for electric field lines? Check all that apply. a. Electric field lines can never intersect b. Electric field lines point away from positive charges and toward negative charges c. Electric field lines are close together in regions of space where the magnitude the electric field is weak and are father apart where it is strong d. At every point in space, the electric field vector at that point is tangent to the electric field line through that point e. Electric field lines are continuous; they do not have a beginning or an ending.
a, b, d
Which of the following statements are true? Check all that apply. a. An equipotential surface is a three-dimensional surface on which the electric potential is the same at every point. b. Electric field lines and equipotential surfaces are always mutually perpendicular. c. The potential energy of a test charge decreases as it moves along an equipotential surface. d. The potential energy of a test charge increases as it moves along an equipotential surface. e. When all charges are at rest, the surface of a conductor is always an equipotential surface.
a, b, e
Fig. 21-12 shows two electric charges of equal magnitudes and opposite signs. Electric field lines surrounding the charges are also shown. Which of the shown arrows correctly represents the electric field vector at point P? a. A b. B c. C d. D e. The electric field is zero at point P.
a.
In deriving the axial electric field for the ring-shaped charge distribution and the electric field from a long line of charge, the component perpendicular to the resulting field is zero because of what physical property? a. symmetry b. only net charge is important c. integration d. positive and negative charges cancel e. superposition
a.
In the figure, a uniform electric field is shown passing through a flat area A. In (a), the surface of area A is perpendicular to the electric field. In (b), the surface is tilted by an angle θ with respect to the electric field. In (c), the surface is parallel to the electric field. In which orientation is the electric flux through the surface the equal to zero? a. The electric flux is the zero through the surface shown in (c). b. The electric flux is the zero through the surface shown in (b) c. The electric flux is zero through all of the surfaces shown d. The electric flux is the zero through the surface shown in (a) e. The electric flux is nonzero and equal through all of the surfaces shown.
a.
Three equal point charges are placed at the corners of a square of side d as shown in Fig. 21-8. Which of the arrows shown represents the direction of the net electric field at the center of the square? a. A b. B c. C d. D e. none of the above
a.
An electron and a proton, are released simultaneously from rest and start to move towards each other because of the attractive Coulomb force between them. They are initially separated by a distance d. The two particles eventually collide. When they collide, a. they are at the midpoint of their initial separation b. they are closer to the proton's initial position c. they are closer to the electron's initial position d. Not enough data is given to predict where they collide.
b
An equipotential surface must be a. oriented 60° with respect to the electric field at every point. b. perpendicular to the electric field at every point c. oriented 30° with respect to the electric field at every point d. parallel to the electric field at every point e. equal to the electric field at every point.
b
Fig. 22-1 shows four Gaussian surfaces surrounding a distribution of charges. Which Gaussian surfaces have an electric flux of +q/εothrough them? a. b. c. d. b and c e. b and d.
b
Four point charges of equal magnitude and varying signs are arranged on corners of the square of side d as shown in Fig. 21-4. Which of the arrows shown represents the net force acting on the charge at the upper right hand corner of the square? a. A b. B c. C d. D e. none of the above
b
In the figure, a uniform electric field is shown passing through a flat area A. In (a), the surface of area A is perpendicular to the electric field. In (b), the surface is tilted by an angle θ with respect to the electric field. In (c), the surface is parallel to the electric field. In which orientation is the electric flux through the surface the largest? a. The electric flux is zero through all of the surfaces shown b. The electric flux is the largest through the surface shown in (a) c. The electric flux is nonzero and equal through all of the surfaces shown d. The electric flux is the largest through the surface shown in (c) e. The electric flux is the largest through the surface shown in (b).
b
Three equal charges are at three of the corners of a square of side d. A fourth charge of equal magnitude is at the center of the square as shown in Fig. 21-1. Which of the arrows shown represents the net force acting on the charge at the center of the square? a. A b. B c. C d. D e. none of the above
b
Two charged objects are separated by some distance. The charge on the first object is greater than the charge on the second object. How does the force between the two objects compare? a. The charged objects exert electrostatic forces on each other that are equal in magnitude and pointing in the same direction b. The charged objects exert electrostatic forces on each other that are equal in magnitude and opposite in direction c. The second object exerts a large electrostatic force on the first object d. The first object exerts a large electrostatic force on the second object.
b
When a point charge of +q is placed on one corner of a square, an electric field strength of 2 N/CN/C is observed at the center of the square. Suppose three identical charges of +q are placed on the remaining three corners of the square. What is the magnitude of the net electric field at the center of the square? a. The magnitude of the net electric field at the center of the square is 6 N b. The magnitude of the net electric field at the center of the square is 0 N c. The magnitude of the net electric field at the center of the square is 2 N d. The magnitude of the net electric field at the center of the square is 8 N e. The magnitude of the net electric field at the center of the square is 4 N.
b
When atom A loses an electron to atom B, a. atom A acquires more neutrons than atom B b. atom A becomes a positive ion and atom B becomes a negative ion c. atom A becomes a negative ion and atom B becomes a positive ion d. atom A becomes more negative than atom B e. atom A acquires less neutrons than atom B.
b
When five equal positive charges are uniformly spaced along the x-axis, the force on the next to last charge on the right is directed a. to the left b. to the right c. possibly in the positive y-direction d. zero e. possibly in the negative y-direction.
b
A disk with a radius of R is oriented with its normal unit vector at an angle θ with respect to a uniform electric field. Which of the following would result in an increase in the electric flux through the disk? Check all that apply. a. decreasing the area of the disk b. decreasing the given orientation angle of the disk c. increasing the given orientation angle of the disk, but not exceeding an angle of 90° d. increasing the strength of the electric field e. decreasing the strength of the electric field f. increasing the area of the disk
b, d, f
A negative charge moves in the direction of an electric field. Which of the following statements are true? Check all that apply. a. The amount of work done on the charge cannot be determined without additional information. b. The electric field does negative work on the charge. c. The electric field does not do any work on the charge. d. The potential energy associated with the charge decreases. e. The potential energy associated with the charge increases. f. The electric field does positive work on the charge.
b, e
Is it possible for the electric field between two positive charges to equal zero along the line joining the two charges? a. Yes, but only if the two charges are equal in magnitude b. Yes, regardless of the magnitude of the two charges c. No, a zero electric field cannot exist between the two charges d. This cannot be determined without knowing the separation between the two charges.
b.
The strength of the electric field at a certain distance from a point charge is represented by E. What is the strength of the electric field at twice the distance from the point charge? a. At twice the distance, the strength of the field is E/2 b. At twice the distance, the strength of the field is E/4 c. At twice the distance, the strength of the field remains equal to E d. At twice the distance, the strength of the field is 4E e. At twice the distance, the strength of the field is 2E.
b.
A small charged ball is inserted into a balloon. The balloon is then blown up slowly. a) Describe how the total flux through the balloon's surface changes as the balloon is blown up. a. The total flux through the balloon's surface will decrease b. The total flux through the balloon's surface will not change c. The total flux through the balloon's surface will increase. b) Describe how the flux per unit surface area of the balloon changes. a. The flux per unit surface area will decrease b. The flux per unit surface area will not change c. The flux per unit surface area will increase.
b; a
A negatively charged rod is brought near one end of an uncharged metal bar. The end of the metal bar farthest from the charged rod will be charged a. positive b. neutral c. negative d. none of the given answers
c
A net charge is placed on a hollow conducting isolated sphere. How does the net charge distribute itself? a. The net charge uniformly distributes itself on the sphere's inner and outer surfaces b. The net charge uniformly distributes itself throughout the thickness of the conducting sphere. c. The net charge uniformly distributes itself on the sphere's outer surface. d. The net charge clumps together at some location within the sphere e. The net charge uniformly distributes itself on the sphere's inner surface.
c
A neutral atom always has a. more neutrons than electrons b. the same number of neutrons as protons c. the same number of protons as electrons d. more protons than electrons e. more neutrons than protons.
c
A positive charge Q is located at the center of an imaginary Gaussian cube of sides aa. The flux of the electric field through the surface of the cube is Φ. A second, negative charge −Q is placed next to Q inside the cube. Which of the following statements will be true in this case? a. The magnitude of the net electric field is constant on the entire surface of the cube b. The net flux through the surface is equal to 2Φ c. The net flux through the surface of the cube is equal to zero d. The electric field on the surface of the cube is perpendicular to the surface e. The net electric field on the surface of the cube is equal to zero
c
A positive charge moves in a direction opposite to that of an electric field. What happens to the energy associated with the charge? a. The electric potential energy of the charge decreases, and the kinetic energy increases. b. Both the electric potential energy and the kinetic energy of the charge increase. c. The electric potential energy of the charge increases, and the kinetic energy decreases. d. Both the electric potential energy and the kinetic energy of the charge decrease.
c
Fig. 22-1 shows four Gaussian surfaces surrounding a distribution of charges. Which Gaussian surfaces have no electric flux through them? a. b. c. d. b and c e. b and d.
c
Five point charges q and four Gaussian surfaces S are shown in the figure. What is the total electric flux through surface S2? a. q/εo b. zero c. 2q/εo d. 4q/εo e. 5q/εo f. 3q/εo
c
Is it possible to have a zero electric field value between a negative and positive charge along the line joining the two charges? a. Yes, regardless of the magnitude of the two charges b. Yes, if the two charges are equal in magnitude c. No, a zero electric field cannot exist between the two charges d. cannot be determined without knowing the separation between the two charges e. cannot be determined without knowing the magnitude of the charges
c
Materials in which the electrons are bound very loosely to the nuclei and can move about freely within the material are referred to as a. polar b. semiconductors c. conductors d. insulators e. superconductors.
c
The number of protons in the nucleus of an electrically neutral atom is equal to a. the number of electrons in the nucleus b. the number of neutrons in the nucleus c. the number of electrons surrounding the nucleus d. the number of neutrons surrounding the nucleus e. None of the other choices is correct.
c
Two charged objects separated by some distance attract each other. If the charges on both objects are doubled with no change in distance between them, what happens to the magnitude of the force between the objects? a. The force between them also doubles b. The force between them is quartered c. The force between them quadruples d. The force between them remains unchanged e. The force between them is halved.
c
Three equal point charges are placed at three of the corners of a square of side d as shown in Fig. 21-9. Which of the arrows shown represents the direction of the net electric field at the center of the square? a. A b. B c. C d. D e. none of the above
c.
A charge Q is positioned at the center of a sphere of radius RR. The flux of the electric field through the sphere is equal to Φ. If the charge Q is now placed at the center of a cube the flux of the electric field through the surface of the cube is equal to a. 2Φ b. 0 c. Φ/2 d. Φ e. The value of the flux depends on the dimensions of the cube.
d
A negative charge moves in a direction opposite to that of an electric field. What happens to the energy associated with the charge? a. Both the electric potential energy and the kinetic energy of the charge increase. b. Both the electric potential energy and the kinetic energy of the charge decrease. c. The electric potential energy of the charge increases, and the kinetic energy decreases. d. The electric potential energy of the charge decreases, and the kinetic energy increases.
d
A negative charge, if free, tries to move a. in the direction of the electric field. b. from high potential to low potential c. away from infinity d. from low potential to high potential e. toward infinity.
d
A plastic rod is rubbed with a fur. During the rubbing process, the rod acquires a negative charge. What type of charge does the fur acquire? a. The fur also acquires a negative charge b. The fur remains neutral c. The fur acquires either a negative or positive charge, depending on how hard the rod was rubbed d. The fur acquires a positive charge.
d
A positively charged rod is brought close to one end of an uncharged metal rod but does not actually touch it. What type of charge does the end of the metal rod closest to the positively charged rod acquire? a. The end of the metal rod closest to the positively charged rod can acquire either a positive or negative charge, depending on the composition of the metal b. The end of the metal rod closest to the positively charged rod acquires a positive charge c. The end of the metal rod closest to the positively charged rod remains neutral d. The end of the metal rod closest to the positively charged rod acquires a negative charge.
d
A solid conducting sphere is placed in an external uniform electric field. With regard to the electric field on the sphere's interior, which statement is correct? a. The interior field points in a direction opposite to the exterior field b. The interior field points in a direction perpendicular to the exterior field. c. The interior field points in a direction parallel to the exterior field. d. There is no electric field on the interior of the conducting sphere.
d
Five point charges q and four Gaussian surfaces S are shown. What is the total electric flux through surface S4? a. 5q/εo b. zero c. q/εo d. 2q/εo e. 4q/εo f. 3q/εo
d
Four equal negative point charges are located at the corners of a square, their positions in the x-y plane being (1, 1), (-1, 1), The direction of the electric field on the x-axis at (1, 0) is a. i b. k c. j d. -i e. -j
d
Four point charges of equal magnitude and sign are arranged on the corners of the square of side d as shown in Fig. 21-5. Which of the arrows shown represents the net force acting on the charge at the upper right hand corner of the square? a. A b. B c. C d. D e. none of the above
d
Outside a spherically symmetric charge distribution of net charge Q, Gauss's law can be used to show that the electric field at a given distance a. must be greater than zero b. must be zero c. must be directed outward d. acts like it is formed by a point charge Q at the center of the distribution e. must be directed inward.
d
The direction of the electric field halfway between an electron and a proton is a. perpendicular to the line from the electron to the proton b. undefined since the electric field is zero c. directed toward the proton d. directed toward the electron e. cannot be determined.
d
Two charged objects are separated by a distance d. The first charge is larger in magnitude than the second charge. a. The first charge exerts a larger force on the second charge b. The second charge exerts a larger force on the first charge c. The charges exert forces on each other equal in magnitude and pointing in the same direction d. The charges exert forces on each other equal in magnitude and opposite in direction.
d
When static equilibrium is established for a charged conductor, the electric field just inside the surface of the conductor is a. opposite to the field outside b. equal to the perpendicular component of the field outside c. equal to the field outside d. zero e. cannot be determined.
d
Five point charges q and four Gaussian surfaces S are represented in the figure shown. Through which of the Gaussian surfaces are the total electric flux zero? a. The total electric flux is not zero through any of the Gaussian surfaces b. S2 c.S4 d. S1 e. S3
d, e
A conductor is placed in an electric field under electrostatic conditions. Which of the following statements is correct for this situation? a. The electric field is zero inside the conductor b. The electric field on the surface of the conductor is perpendicular to the surface c. A certain fraction of the valence electrons go to the surface of the conductor d. All of the previous answers apply e. None of the answers apply.
d.
At a particular location, the electric field points due north. a) In what direction(s) will the rate of change of potential be most positive? Check all that apply. a. east b. west c. north d. south b) In what direction(s) will the rate of change of potential be most negative? Check all that apply. a. east b. west c. north d. south c) In what direction(s) will the rate of change of potential be zero? Check all that apply. a. east b. west c. north d. south
d; c; a,b
Consider a spherical Gaussian surface of radius R centered at the origin. A charge Q is placed inside the sphere. Where should the charge be located to maximize the magnitude of the flux of the electric field through the Gaussian surface? a. at the original b. at x = 0, y = 0, z = R/2 c. at x = R/2, y = 0, z = 0 d. at x = 0, y = R/2, z = 0 e. The flux does not depend on the position of the charge as long as it is inside the sphere
e
Electric dipoles always consist of two charges that are a. equal in magnitude; both are positive. b. unequal in magnitude; both are negative. c. equal in magnitude; both are negative. d. unequal in magnitude; opposite in sign. e. equal in magnitude; opposite in sign.
e
Gaussian surfaces A and B enclose the same positive charge +Q. The area of Gaussian surface A is three times larger than that of Gaussian surface B. The flux of electric field through Gaussian surface A is a. nine times larger than the flux of electric field through Gaussian surface B. b. unrelated to the flux of electric field through Gaussian surface B. c. three times larger than the flux of electric field through Gaussian surface B. d. three times smaller than the flux of electric field through Gaussian surface B. e. equal to the flux of electric field through Gaussian surface B.
e
Gaussian surfaces A and B enclose the same positive point charge. The area of surface A is two times larger than that of surface B. How does the total electric flux through the two surfaces compare? a. The total electric flux through surface B is eight times larger than that through surface A. b. The total electric flux through surface A is four times larger than that through surface B. c. The total electric flux through surface B is four times larger than that through surface A. d. The total electric flux through surface A is eight times larger than that through surface B. e. The total electric flux through the two surfaces is equal.
e
If the electric flux through a rectangular area is 5.0 Nm2/C, and the electric field is then doubled, what is the resulting flux through the area? a. 5.0 Nm2/C b. 1 Nm2/C c. 2.5 Nm2/C d. 20 Nm2/C e. 10 Nm2/C
e
One electron-volt corresponds to a. 8.0 × 10-20 J. b. 8.0 × 10-20 J. c. 1.9 × 10-16 J. d. 9.5 × 10-17 J. e. 1.6 × 10-19 J.
e
Fig. 21-11 shows 3 electric charges labeled Q1, Q2, Q3 and some electric field lines in the region surrounding the charges. What are the signs of the 3 charges? a. All 3 charges are negative b. All 3 charges are positive c. Q1 is negative, Q2 is positive, Q3 is negative d. Q1 is positive, Q2 is positive, Q3 is negative e. Q1 is positive, Q2 is negative, Q3 is positive.
e.
Two large, flat, horizontally oriented plates are parallel to each other, a distance d apart. Half-way between the two plates the electric field field has a magnitude E. If the separation of the plates is reduced to d/2 what is the magnitude of the electric field half-way between the plates? a. 4E b. 2E c. 0 d. E/2 e. E
e.
True or false: Electric field lines can cross only if both positive and negative charges are involved.
false
True or false: Gauss's law can be applied using any surface.
false
True or false: Gauss's law may be applied only to charge distributions that are symmetric.
false
True or false: If the net flux through a closed surface is zero, then there can be no charge or charges within that surface.
false
True or false: When a proton moves in a direction of the electric field, its potential increases but its potential energy decreases.
false
Yes or no: Is the electric field E⃗→ in Gauss's law, ∮E⃗⋅dA⃗=Qencl/ε0, created only by the charge Qencl?
no
Yes or no: Would Gauss's law be helpful in determining the electric field due to an electric dipole?
no
True or false: A positive charge placed in an electric field experiences a force in the direction of the field.
true
True or false: Equipotential lines and electric field lines meet perpendicular to one another.
true
True or false: Every point on an equipotential surface is at the same potential.
true
True or false: If a closed surface surrounds a dipole, the net flux through the surface is zero.
true
True or false: If a conductor is placed in an electric field under electrostatic conditions, the electric field is excluded from the inside of the conductor.
true
True or false: If the net flux through a closed surface is positive, then the net charge enclosed must be positive.
true
True or false: The component of the electric field in any direction is equal to the negative of the rate of change of the electric potential with distance in that direction.
true
True or false: The direction of an electric field is from higher to lower potential.
true
True or false: The potential outside a uniformly charged sphere is the same as if all the charge were concentrated at its center.
true
Yes or no: The electric field E⃗→ is zero at all points on a closed surface; is there necessarily no net charge within the surface? If a surface encloses zero net charge, is the electric field necessarily zero at all points on the surface?
yes; no
