Exam 1 Practice
Two point charges, initially 2.0 cm apart, experience a 1.0-N force. If they are moved to a new separation of 8.0 cm, what is the electric force between them?
A. |
4.0 N |
B. |
16 N |
C. |
1/4 N |
D. |
1/16 N |
Sphere A carries a net charge and sphere B is neutral. They are placed near each other on an insulated table. Which statement best describes the electrostatic force between them?
A. |
There is no force between them since one is neutral. |
B. |
There is a force of repulsion between them. |
C. |
There is a force of attraction between them. |
D. |
The force is attractive if A is charged positively and repulsive if A is charged negatively. |
Three identical point charges of 2.0 æC are placed on the x-axis. The first charge is at the origin, the second to the right at x = 50 cm, and the third is at the 100 cm mark. What are the magnitude and direction of the electrostatic force which acts on the charge at the origin?
A. |
0.18 N left |
B. |
0.18 N right |
C. |
0.36 N left |
D. |
0.36 N right |
Electric field lines
A. |
circle clockwise around positive charges. |
B. |
circle counter-clockwise around positive charges. |
C. |
radiate outward from negative charges. |
D. |
radiate outward from positive charges. |
A force of 6.0 N acts on a charge of 3.0 æC when it is placed in a uniform electric field. What is the magnitude of this electric field?
A. |
18 MN/C |
B. |
2.0 MN/C |
C. |
0.50 MN/C |
D. |
130 MN/C |
A 5.0-C charge is 10 m from a small test charge of 1.0 nC. What is the direction of the electric field at the 1.0 nC charge?
A. |
toward the 5.0 C |
B. |
away from the 5.0 C |
C. |
perpendicular to a line joining the charges |
D. |
none of the above |
A 5.0-æC charge is placed at the 0 cm mark of a meterstick and a -4.0 æC charge is placed at the 50 cm mark. At what point on a line joining the two charges is the electric field zero?
A. |
1.4 m from the 0 cm mark |
B. |
2.9 m from the 0 cm mark |
C. |
3.3 m from the 0 cm mark |
D. |
4.7 m from the 0 cm mark |
A metal sphere of radius 10 cm carries a charge of +2.0 æC. What is the magnitude of the electric field 5.0 cm from the sphere's surface?
A. |
4.0X105 N/C |
B. |
8.0X105 N/C |
C. |
4.0X107 N/C |
D. |
8.0X107 N/C |
The net work done in moving an electron from point A, where the potential is -50 V, to point B, where the potential is +50 V, is
A. |
+1.6X10-17 J |
B. |
-1.6X10-17 J |
C. |
zero |
D. |
none of the above. |
Starting from rest, a proton falls through a potential difference of 1200 V. What speed does it acquire?
A. |
1.2X105 m/s |
B. |
2.4X105 m/s |
C. |
3.6X105 m/s |
D. |
4.8X105 m/s |
For an electron moving in a direction opposite to the electric field
A. |
its potential energy increases and its potential decreases. |
B. |
its potential energy decreases and its potential increases. |
C. |
its potential energy increases and its potential increases. |
D. |
its potential energy decreases and its potential decreases. |
How much work does 9.0 V do in moving 8.5X1018 electrons?
A. |
12 J |
B. |
7.7 J |
C. |
1.4 J |
D. |
1.1 J |
A uniform electric field, with a magnitude of 500 V/m, is directed parallel to the +x axis. If the potential at x = 5.0 m is 2500 V, what is the potential at x = 2.0 m?
A. |
500 V |
B. |
1000 V |
C. |
2000 V |
D. |
4000 V |
The absolute potential at a distance of 2.0 m from a negative point charge is -100 V. What is the absolute potential 4.0 m away from the same point charge?
A. |
-25 V |
B. |
-50 V |
C. |
-200 V |
D. |
-400 V |
The absolute potential at the center of a square is 3.0 V when a charge of +Q is located at one of the square's corners. What is the absolute potential at the square's center when a second charge of -Q is placed at one of the remaining corners?
A. |
zero |
B. |
3.0 V |
C. |
6.0 V |
D. |
9.0 V |
A parallel-plate capacitor consists of plates of area 1.5X10-4 m2 and separated by 1.0 mm. The capacitor is connected to a 12-V battery. What is the charge on the plates?
A. |
1.6X10-11 C |
B. |
3.2X10-11 C |
C. |
1.6X10-14 C |
D. |
3.2X10-14 C |
A parallel plate capacitor is constructed with plate area of 0.40 m2 and a plate separation of 0.10 mm. How much charge is stored on it when it is charged to a potential difference of 12 V?
A. |
0.21 æC |
B. |
0.42 æC |
C. |
0.63 æC |
D. |
0.84 æC |
A parallel plate capacitor is constructed with plate area of 0.40 m2 and a plate separation of 0.10 mm. How much energy is stored?
A. |
2.5 æJ |
B. |
5.0 æJ |
C. |
7.5 æJ |
D. |
10 æJ |
A 15-æF capacitor is connected to a 50-V battery and becomes fully charged. The battery is removed and a slab of dielectric that completely fills the space between the plates is inserted. If the dielectric has a dielectric constant of 5.0, what is the capacitance of the capacitor after the slab is inserted?
A. |
75 æF |
B. |
20 æF |
C. |
3.0 æF |
D. |
1.0 æF |
A 15-æF capacitor is connected to a 50-V battery and becomes fully charged. The battery is removed and a slab of dielectric that completely fills the space between the plates is inserted. If the dielectric has a dielectric constant of 5.0, what is the voltage across the capacitor's plates after the slab is inserted?
A. |
250 V |
B. |
10 V |
C. |
2.0 V |
D. |
0.75 V |