Chapters 24 (021)
Find the electric potential at the center of a charged
metal sphere of radius 15 cm if the electric field at its
surface is 1.2*10**4 N/C.
A1
A2
A3
A4
A5
1.8 kV
1.2 kV
2.7 kV
zero
Infinity
The electric potential at point A in an electric field is 15
V smaller than at point B. If a charge q = -2.0 C is moved
from A to B, then the electric potential energy of this
charge will:
A1
A2
A3
A4
A5
decrease by 30 J.
increase by 30 J.
increase by 15 J.
decrease by 15 J.
increase by 25 J.
Two electrons are fixed 2.0 cm apart. Another electron is
shot from infinity with a speed v and comes to rest at a
point midway between the two electrons. Find v.
A1
A2
A3
A4
318
963
255
612
m/s
m/s
m/s
m/s
A5
742 m/s
Over a certain region, the electric potential is given (in
volts) as
V = (3.0*(x**2)*y)+(y**2)+(y*z).
Find the magnitude of the electric field at the point
(1.0,1.0,1.0), where all distances are in meters.
A1
A2
A3
A4
A5
8.5 N/C
2.4 N/C
1.0 N/C
3.6 N/C
zero
S-25-1
The gap between electrodes in a spark plug is 0.060 cm. To
produce an electric spark in a gasoline-air mixture, an electric
field of 3.0 x 106 V/m must be achieved. When starting the car,
what minimum voltage must be supplied by the ignition circuit?
S-25-16
A positron has the same charge as a proton, but the same mass
as an electron. Suppose a positron moves 5.2 cm in the direction
of a uniform 480 V/m electric field. How much potential energy
does it gain or lose? How much kinetic energy?
S-25-22
A small spherical object carries a charge of 8.0 nC. At what
distance from the center of the object is the potential equal to
100V? 50V? 25V? Is the spacing of the equipotentials
proportional to the change in V?
S-25-26
A charge q (q>0) is at the origin. A charge –2q is at x = 2 m on
the x-axis. For what values of x is the electric potential equal to
zero? the electric field equal to zero?
S-25-38
The electric potential (in volts) in a certain region is:
V = 4xz – 5y + 3z2
Find the direction and magnitude of the electric field at the point
P(2, -1, 3), where all the distances are in meters.
S-25-51
How many electrons should be removed from an initially
uncharged spherical conductor of radius 0.300 m to produce a
potential of 7.50 kV at the surface? What would the potential be
at the center of the sphere?