Download Electric Potential

Q1) A rocket blasts off from earth on its way to rendezvous with
the International Space Station. Which picture of point charges
has a change in electrical potential energy analogous to the change
in gravitational potential energy for the rocket ship?
Q2) Which of the following situations will result in an increase in
electric potential energy?
a) Two like charges are moved closer together.
b) Two like charges are moved farther apart.
c) Two opposite charges are moved closer together.
d) Two opposite charges are moved farther apart.
1) b & d
2) b & c
3) a & c
4) a & d
Q3) A charge q=-4.0 C is moved 0.25 m horizontally to point P in
a region where an electric field is 150 N/C and directed vertically
as shown. Is the change in electric potential energy of the charge
positive, negative, or zero?
1) positive
2) negative
3) zero
Q4) In the figure, a proton moves from point i to point f in a
uniform electric field directed as shown. Does the electric potential
energy of the proton increase or decrease?
1) increase
2) decrease 3) not enough information
Q5) When a positive charge moves in the direction of the electric
field,
1)
2)
3)
4)
5)
the charge increases.
the field does work on the charge.
the charge does work on the field.
the charge gains potential energy.
the charge loses kinetic energy.
Q6) A charge -q is far away from a charge -Q which is fixed in
place. As -q moves closer to -Q, the work done by the electric field
is
1) positive.
2) negative.
3) zero.
Q7) Two test charges are brought separately into the vicinity of a
charge +Q. First, test charge +q is brought to a point a distance r
from +Q. Then this charge is removed and test charge –q is
brought to the same point. The electrostatic potential energy of
which test charge is greater:
1) +q
2) –q
3) It is the same for both.
Q8) A negative charge –q is moved from position i to position f
between the plates of a charged capacitor as shown. As the test
charge –q was moved from i to f, the potential energy (PE)
increased or decreased and the voltage (V) at the position of the
test charge increased or decreased.
1) PE increased and V decreased.
2) PE decreased and V increased.
3) PE increased and V increased.
4) PE decreased and V decreased.
5) None of these.
E
+
+
-
+
+
+
+
-
-q
(f)
x
(i)
-
+
-
+
-
+
-
Q9) The figure below shows three paths along which we can move
positively charged sphere A closer to positively charged sphere B, which
is fixed in place. (a) Would sphere A be moved to a higher or lower
electric potential? (b) Is the work done by the electric field (due to the
second sphere) positive, negative, or zero?
1) (a) higher
2) (a) higher
3) (a) lower
4) (a) lower
5) (a) lower
(b) positive
(b) negative
(b) positive
(b) negative
(b) zero
Q10) An electron volt is:
1) the force acting on an electron in a field of 1N=C
2) the force required to move an electron 1 meter
3) the energy gained by an electron in moving through a potential
difference of 1 volt
4) the energy needed to move an electron through 1 meter in any
electric field
5) the work done when 1 coulomb of charge is moved through a
potential difference of 1 volt.
Q17-4) Positive charges will accelerate from a region of
higher potential to a region of lower potential.
1) true
2) false
Q11) In a certain region of space, the potential is constant. In this
same region, then, the electric field is
1) positive.
2) negative.
3) zero.
Q12) An electron is pushed into an electric field where it acquires
a 1-V electrical potential. Suppose instead that two electrons are
pushed the same distance into the same electric field. The electrical
potential of the two electrons is
1) 0.25 V.
2) 0.5 V.
3) 1 V.
4) 2 V.
5) 4 V.
Q13) In a certain region of space the electric potential increases
uniformly from east to west and does not vary in any other
direction. The electric field:
1) points east and varies with position
2) points east and does not vary with position
3) points west and varies with position
4) points west and does not vary with position
5) points north and does not vary with position
Q14) Two point charges are each near another point charge
+Q. Charge +q is a distance r from +Q. Charge +2q is a
distance 2r from +Q. Compared with the electrostatic
potential of the +q charge at A, that of the +2q charge at B is
1) greater
2) smaller
3) the same
Q15) A beam of electrons is deflected as it moves between
oppositely charged parallel plates. Which plate is at the higher
potential?
1) The upper plate.
2) The lower plate.
3) They are at the same potential.
Q16) A point charge is placed in an electric field that varies with
location. No force is exerted on this charge:
1) at locations where the potential is zero.
2) if the charge is moving along an equipotential line.
3) if the charge is moving perpendicular to an equipotential line.
4) None of the above statements is true.
Q17) A non-uniform electric field is represented by electric field
lines. Rank the electric potential of the points indicated from
greatest to least.
1) A < B < D < C < E
2) B < A < C < E < D
3) B < A < C = E < D
4) A = B < C < E < D
Q18) Which one of the following statements concerning
electrostatic situations is false?
1) E is zero everywhere inside a conductor.
2) Equipotential surfaces are always perpendicular to E.
3) It takes zero work to move a charge along an equipotential
surface.
4) If V is constant throughout a region of space then E must be
zero in that region.
5) No force component acts along the path of a charge as it is
moved along an equipotential surface.
Q19) The figure below shows the equipotential
curves around a tree that is struck by lightning.
Which cow is most likely to be killed?
1) Cow A; it sees a greater potential difference.
2) Cow B, because it is at a higher potential.
3) Both cows are too close to the tree to live.
Q20) An electron goes from one equipotential surface to
another along one of the four paths shown below. Rank the
paths according to the work done by the electric field,
greatest first.
1) 1, 3, 2 and 4 tie
2) 3, 2 and 4 tie, 1
3) 1, 2 and 4 tie, 3
4) 4 and 2 tie, 3, 1
5) none of the above
Q21) The figure shows three pairs of parallel plates. The electric field
between the plates is uniform and perpendicular to the plates. (a) For
which pair(s) is the electric field pointing rightward? (b) If an electron is
released midway between the third pair of plates, what does it do?
1) (a) 1& 2
2) (a) 1 & 2
3) (a) 3
4) (a) 3
5) (a) 1, 2, & 3
(b) accelerate left
(b) accelerate right
(b) accelerate left
(b) accelerate right
(b) accelerate left
Q22) Choose the correct statement:
1) A proton tends to go from a region of low potential to a region
of high potential
2) The potential of a negatively charged conductor must be negative
3) If E = 0 at a point P then V must be zero at P
4) If V = 0 at a point P then E must be zero at P
5) None of the above are correct
Q23) Two identical charges, +Q and +Q, are fixed in space. The
electric field at the point midway between the charges is zero.
The voltage at that point is.
1) Zero
2) Non-zero.
Q24) Two equal and opposite charges +Q and –Q are fixed in
space. The voltage at the point midway between the charges is
zero. The electric field at that point is..
1) Zero
2) Non-zero.
Q25) The figure here shows three arrangements of two protons.
Rank the arrangements according to the net electric potential
produced at point P by the protons, greatest first.
1) a, b, c
2) c, b, a
3) c, a, b
4) b, a, c
5) none of the above
Q26) A +1.0 μC point charge is moved from point A to B in the
uniform electric field as shown. Which one of the following
statements is necessarily true concerning the potential energy of
the point charge?
1) It increases by 6.0×10−6 J.
2) It decreases by 6.0×10−6 J.
3) It decreases by 9.0×10−6 J.
4) It increases by 10.8×10−6 J.
5) It decreases by 10.8×10−6 J.
Q27) Four charges, all of the same magnitude
Q, are arranged in a square as shown. The two
top charges are positive, the two bottom
charges are negative. The voltage at A is
1) +
2) 
3) 0
Q28) Four charges, all of the same magnitude
Q, are arranged in a square as shown. The two
top charges are positive, the two bottom
charges are negative. The magnitude of the
electric field at A is
+
Q
A
B
-Q
+
Q
+
Q
C
-Q
A
B
-Q
+
Q
C
-Q
1) non-zero
2) zero
Q29) Four charges, all of the same magnitude
Q, are arranged in a square as shown. The two
top charges are positive, the two bottom
charges are negative. The voltage at C is
1) +
2) 
3) 0
+
Q
A
B
-Q
+
Q
C
-Q
Q30) Consider a capacitor made of two isolated parallel metal
plates separated by a distance d. The top plate is positively
charged with total charge +Q; the bottom plate is negatively
charged with total charge -Q. A slab of metal of thickness L < d is
inserted between the plates, not connected to either one. Upon
insertion of the metal slab, the voltage difference between the
plates
1) increases
2) decreases
3) remains constant.
Q31) The figure shows three pairs of parallel plates with the same
separation, and the electric potential of each plate. The electric
field between the plates is uniform and perpendicular to the plates.
In which pair is the magnitude of the electric field between the
plates the greatest.
1) 1
4) two tie
2) 2
5) all tie
3) 3
Q32) A solid spherical conductor is given a net nonzero charge.
The electrostatic potential of the conductor is
1) largest at the center.
2) largest on the surface.
3) largest somewhere between center and surface.
4) constant throughout the volume.
Q33) Consider two isolated spherical conductors each having net
charge Q. The spheres have radii a and b, where b>a. Which
sphere has the higher potential?
1) the sphere of radius a
2) the sphere of radius b
3) They have the same potential.
Q34) A spherical conductor with charge Q has a potential V a
distance r away. What is the potential at a distance of 2r from a
spherical conductor with charge 2Q?
1) V/4
2) V/2
3) V
4) 2V
Q35) An electron and a proton, both initially at rest, are
accelerated through a potential difference +V and -V, respectively.
Is the final speed of the proton greater than, less than, or equal to
the speed of the electron?
1) greater than
2) less than
3) equal to
4) can't tell without knowing V
Q36) An electron is accelerated from rest through a potential
difference V . Its final speed is proportional to:
1) V
4) 1/V1/2
2) V2
5) 1/V
3) V1/2
Q37) In separate experiments, four different particles each start from far
away with the same speed and impinge directly on a gold nucleus. The
masses and charges of the particles are
particle 1: mass m0, charge q0
particle 2: mass 2m0, charge 2q0
particle 3: mass 2m0, charge q0/2
particle 4: mass m0/2, charge 2q0
Rank the particles according to the distance of closest approach to the gold
nucleus, from smallest to largest.
1) 1, 2, 3, 4
4) 4, 1 and 2 tie, then 1
2) 4, 3, 2, 1
3) 3, 1 and 2 tie, then 4
5) 1 and 2 tie, then 3, 4
Q38) A conducting sphere with radius R is in electrostatic
equilibrium. A plot of the potential inside the sphere is best
represented by ___.
1) A
2) B
3) C
Q39) Positive charge is distributed uniformly throughout a nonconducting sphere. The highest electric potential occurs:
1) at the center
2) at the surface
3) halfway between the center and surface
4) just outside the surface
5) far from the sphere
Q40) Two conducting spheres, one having twice the diameter of the other,
are separated by a distance large compared to their diameters. The smaller
sphere (1) has charge q and the larger sphere (2) is uncharged. If the
spheres are then connected by a long thin wire:
1) 1 and 2 have the same potential
2) 2 has twice the potential of 1
3) 2 has half the potential of 1
4) 1 and 2 have the same charge
5) all of the charge is dissipated
Q41) Two conducting spheres are far apart. The smaller sphere carries a
total charge Q. The larger sphere has a radius that is twice that of the
smaller and is neutral. After the two spheres are connected by a
conducting wire, the charges on the smaller and larger spheres,
respectively, are:
1) Q/2 and Q/2
2) Q/3 and 2Q/3
3) 2Q/3 and Q/3
4) zero and Q
5) 2Q and -Q
Q42) Two conducting spheres are far apart. Sphere 1 has radius r1
and charge q1 = 10 C. Sphere 2 has radius r2= 2r1 and charge of
q2 = 50 C. After the two spheres are connected by a conducting
wire, the charges on each sphere are:
1) q1 = 10 C; q2 = 50 C
2) q1 = 20 C; q2 = 40 C
3) q1 = 30 C; q2 = 30 C
4) q1 = 40 C; q2 = 20 C
5) q1 = 50 C; q2 = 10 C
Q43) An isolated system consists of two conducting spheres A and B.
Sphere A has five times the radius of sphere B. Initially, the spheres are
given equal amounts of positive charge and are isolated from each other.
The two spheres are then connected by a conducting wire. Note: The
potential of a sphere of radius R that carries a charge Q is V = kQ/R, if the
potential at infinity is zero. Which one of the following statements is true
after the spheres are connected by the wire?
1) The electric potential of A is 1/25 as large as that of B.
2) Both spheres are at the same electric potential.
3) The electric potential of A is 25 times larger than that of B.
4) The electric potential of A is 1/5 as large as that of B.
5) The electric potential of A is five times larger than that of B.
Q44) The figure below shows a thin, uniformly charged rod and
three points at the same distance d from the rod. Without
calculation, rank the magnitude of the electric potential the rod
produces at these three points, greatest first.
1) c, a, b
2) c, b, a
3) a, c, b
4) a, b, c
5) all tie