Multiple choice questions on electrostatics.

Question 1: If there is a force of 5.0 x 10-12 N acting to the left on an electron, the electric field intensity at the location of this electron will be:
a. zero.
b. 8.0 x 10-31 N/C to the left
c. 3.1 x 107 N/C to the left
d. 3.1 x 107 N/C to the right
e. none of these

Question 2: In one mole or 18 grams of water, the total negative charge of all the electrons is:
a. zero because its electrically neutral.
b. less than one C
c. almost 100,000 C.
d. almost one million C.
e. none of these

Question 3: Consider three identical metal spheres that are mounted on insulating stands. Sphere X is neutral, sphere Y has a charge -1q, and sphere Z has a charge +4q. Y and Z are touched together and then separated.
a. Each is now charged, with a charge +1.5 q
b. Each is now charged, with a charge +2.5 q
c. Each is now charged, with a charge +3 q
d. Sphere Y has charge +4 q, sphere Z now has charge -1 q
e. none of these

Question 4: Consider a small, conducting sphere of 0.0010 kg mass. Extra electrons are added to this sphere and an identical sphere below it so that the excess charge on the top sphere is three times that on the lower one. How much extra charge would have to be placed upon the top sphere so that the electrical repulsion between the extra charge on these spheres would provide a force equal to the weight of the sphere when the spheres are 4.0 m apart?
a. 5.8 x 10-12C
b. 2.4 x 10-6 C
c. 3.6 x 10-6 C
d. 7.2 x 10-6 C
e. none of these

Question 5: Consider a small, conducting sphere of 0.0010 kg mass. Extra electrons are placed on this sphere and on an identical sphere 3.0 m below it so the repulsion between these extra electrons provides a force equal to the weight of the top sphere. How many electrons must be added to each sphere?
a. 5.0 x 10-25
b. 3.1 x 10-6
c. 2.0 x 1013
d. 3.9 x 1013
e. none of these

Question 6:
Electrical charge interaction can be summarized by:
a. - charge repels other - charge.
b. + charge repels other + charge.
c. - charge and + charge attract each other.
d. All of these.
e. None of these.

Question 7: Consider two point charges that are separated by a distance, 2r. If this distance between them is increased to 5 r, the force between the charges is:
a. 1/25 as great as it had been
b. 4/25 as great as it had been
c. 1/9 as great as it had been
d. 25 times as great as it had been
e. none of these

Question 8: The electric field is zero:
a. inside any conductor.
b. inside any conductor with a static charge.
c. inside any material, conductor or insulator, with a static charge.
d. Never.
e. Always.

Question 9:
If the symbols ] and [ are used to represent a pair of charged plates, in the sketch below,
+] [-
the field between the two plates would be directed:
a. upward.
b. to the left.
c. to the right.
d. zero, so its direction would be without meaning.
e. none of these

Question 10: Consider three identical metal spheres that are mounted on insulating stands. Sphere X is neutral, sphere Y has a charge -1q, and sphere Z has a charge +4q. X and Y are touched together and then separated.
a. Each is now charged, with a charge -0.5 q.
b. Each is now charged, with a charge -1 q
c. Sphere X is neutral, sphere Y has a charge -1q
d. Sphere X has charge -1 q, sphere Y is now neutral
e. none of these