Download Electrostatics Test 2012

1) The negative charge shown with the velocity and acceleration,
as indicated, is in the presence of an electric field. Which
dashed vector represents the direction of the electric field?
a. A
b. B
c. C
d. D
e. E
2) The Voltage as a result of an electric field changes according to the equation V=7.5x2-180x. Where will
the electric field be zero?
a. 2
b. 4
c. 6
d. 8
e. 12
3) Two positive charges are separated as shown. What best represents the functions of voltage
and electric field on the dashed axis separating the two charges?
a. A
b. B
c. C
d. D
e. E
4) A water molecule is brought close to a large positive charge. Remember, the oxygen end
naturally has a partial negative charge and the hydrogen atoms will naturally have a partial
positive charge, as shown. As the water molecule is brought close which of the following is true
regarding any force or torque applied to the water molecule. In this first instant, the net force
will be___________, and in the first instant torque will be ____________.
a. To the right, clockwise
b. To the right, counter clockwise
c. To the left, clockwise
d. To the left, counterclockwise
e. Zero, clockwise
5) What is the net work done by an external force in bringing the three particles together, as
shown, from a great distance apart? Assume all charges have the same magnitude of e.
6) Considering the electric field lines created by the two charged particles, what is the relative
charge on each particle
shown?
a. 1,-1
b. 2,-1
c. 2,1
d. 2,2
e. 3,2
7) A Hydrogen nucleus (relative mass=1, relative charge=+1) and a helium nucleus (relative
mass=4, relative charge=+2) are accelerated across the same electric potential difference with
the same distance traveled. Which of the following is an accurate statement of the relative ratio
of the hydrogen acceleration to the helium acceleration?
a. 1:2
b. 1:√2
c. 1:1
d. √2:1
e. 2:1
8) How can we compare the following?
1)Force on Q and 2Q as a result of their electric fields
2)F2Q and T
a. 1)FQ>F2Q
2) F2Q >T
b. 1)FQ=F2Q
2) F2Q <T
c. 1)FQ=F2Q
2) F2Q >T
d. 1)FQ=F2Q
2) F2Q =T
e. 1)FQ<F2Q
2) F2Q <T
9) In the diagram shown the outer ring has a negative charge and the inner ring has an equal and
opposite positive charge (not charge density). What would be true regarding the electric field
and voltage some point directly above the rings (perpendicular to the plane of the rings), as
shown?
a. V=- and E is down
b. V=0 and E is down
c. V=0 and E is 0
d. V=0 and E is up
e. V=+ and E is up
10) Assume, in each situation shown, that point A is an equal distance from the center of the shell.
In which situation would the electric
field at A be the greatest?
a. A
b. B
c. C
d. D
e. impossible to determine with
the given information
11) Given the charge densities of each sheet (0, +4, -2, 0, +3) and assuming
the length and width of each sheet is much larger that the separation
distance between those sheets, where is the largest electric field?
a. a
b. b
c. c
d. d
e. cannot determine without the distances between the plates
12) Considering two imaginary spheres (not interfering with the electric field from the rod) enclose
a long rod of uniform charge density per unit length. Sphere A has a radius of 2R and sphere B
has a radius R. What is the correct ratio of the flux through A:B? Assume the rod extents far
beyond the picture and that each sphere is bisected by the rod.
a. 1:2
b. 1:1
c. 2:1
d. 4:1
e. 8:1