Lab 3

Question 1

How much work is required to move a charge of 0.05 C through a potential difference of 6 V?

0.11 J
0.3 J
11 J
3 J

Answer 1

0.3 J

Question 2

Electric field lines must be ____ to the surface of a conductor.

Perpendicular
Parallel
Random
Field lines are not present at the surface of a conductor

Answer 2

Perpendicular

Question 3

The electric field at a point P that is r distance away from a very small ring of charge such that r is much greater than the diameter of the ring is

Directly proportional to the distance r
Directly proportional to the distance r^2
Inversely proportional to the distance
Inversely proportional to the distance r^2

Answer 3

Inversely proportional to the distance r^2

Question 4

According to Coulomb’s law the magnitude of the force of attraction or repulsion between two electric charges, both at rest, varies

A) inversely as the product of the charges and directly as the square of the distance between the charges
B) inversely as the product of the charges and inversely as the square of the distance between the charges
C) directly as the product of the charges and directly as the square of the distance between the charges
D) directly as the product of the charges and inversely as the square of the distance between the charges
E) directly as the product of the charges and inversely as the square root of the distance between the charges

Answer 4

D) directly as the product of the charges and inversely as the square of the distance between the charges

Question 5

Electric field lines must be _____ to any equipotential surface

Perpendicular
Parallel
Tangent
None of the above

Answer 5

Perpendicular

Question 6

A 2 Coulomb charge experiences a force of 20 N. The electric field strength is

10 N/C
20 N/C
30 N/C
40 N/C

Answer 6

10 N/C

Question 7

The nature of an electric field can be studied quantitatively by measuring the

magnitude and direction of the force exerted on a positive test charge
magnitude and direction of the force exerted on a magnetic compass
magnitude and direction of the force exerted on a test mass
magnitude and direction of the force exerted on a neutron
magnitude and direction of the force exerted on a north magnetic pole

Answer 7

magnitude and direction of the force exerted on a positive test charge

Question 8

Two infinite parallel surfaces carry uniform charge densities of 0.20 nC/m^2 and -0.60 nC/m^2. What is the magnitude of the electric field at a point between the two surfaces?

34 N/C
23 N/C
45 N/C
17 N/C
90 N/C

Answer 8

45 N/C

Question 9

A solid circular disk conductor with a cavity at the center carries a total charge of +7 Coulombs. Within the cavity, insulated from the conductor, is a point charge of -2 Coulombs. How much charge is on the inner surface of the conductor

-7 C
-2 C
-5 C
+2 C
+5 C

Answer 9

+2 C

Question 10

When a charged particle is moved along an electric field line,

A) the electric field does no work on the charge.
B) the electrical potential energy of the charge does not change.
C) the electrical potential energy of the charge undergoes the maximum change in magnitude.
D) the voltage changes, but there is no charge in electrical potential energy.
E) the electrical potential energy undergoes the maximum change, but there is no change in voltage.

Answer 10

C) the electrical potential energy of the charge undergoes the maximum change in magnitude.

Question 11

During the experimental procedure if a signal change appears it means there is

No difference in electric potential between the two scope probes
an intersection of electric lines of force
an intersection of equipotential lines
a measurable difference in electric potential between the two probes
a short circuit in your experimental circuit set-up

Answer 11

a measurable difference in electric potential between the two probes

Question 12

Charge of uniform surface density 0.20 nC/m^2 is distributed over the entire xy plane. Determine the magnitude of the electric field at any point having z=2.0m?

17 N/C
11 N/C
23 N/C
28 N/C
40 N/C

Answer 12

11 N/C

Question 13

A solid circular disk conductor with a cavity at the center carries of +7 Coulombs. Within the cavity, insulated form the conductor, is a point charge of -2 Coulombs. How much charge is on the outer surface of the conductor

-7 C
-2 C
-5 C
+2 C
+5 C

Answer 13

+5 C

Question 14

Since work is done only when the net exerted force has some component along the direction of displacement, it necessarily follows that electric lines of force are

A) perpendicular to the equipotential surface everywhere
B) parallel to the equipotential surface everywhere
C) NOT the cause of potential differences
D) NOT the cause of energy stored or released when charged particles are moved from one equipotential surface to another
E) always considered as working forces

Answer 14

A) perpendicular to the equipotential surface everywhere

Question 15

Electric field of a magnitude E is detected at R=10.00m from its source, which is a point charge Q=1.11x10^7 C. What is the magnitude of the electric field (Hint: use k=8.99x10^9 N*m^2/C^2)

9.98 N
9.978989 N/C
10.0 N/C
9.98 N/C
10 N/C

Answer 15

9.98 N/C

Question 16

How much work is done in moving 5.0 C of electric charge from one terminal of a 9.0 V battery to the other?

1.8 J
0.56 J
45 J
60 J
25 kJ

Answer 16

45 J

Question 17

In the field surrounding a positively charged particle the electric field lines of force

are directed radially inward
emanate radially outward
surround the charged particle
form equipotential contours about the charged particle
are randomly dispersed about the charged particle

Answer 17

emanate radially outward

Question 18

If 9.1x10^2 joules of work is done in moving 45.5 C of electric charge from one terminal of a battery to the other, how many volts is the battery providing?

2x10^0
2x10^2
0.050
20.
0.05

Answer 18

20.

Question 19

Which of the following is true?

A) equipotential lines are perpendicular to respective lines of force
B) equipotential lines are parallel to respective lines force
C) families of equipotential lines originate on positive charge
D) work is done only when a charge is moved along an equipotential line or surface
E) when a charge is moved from one equipotential surface the net work done is zero joules

Answer 19

B) equipotential lines are parallel to respective lines force

Question 20

Three uncharged infinite parallel planes are stacked one above the other with a uniform separation of distance d. The upper plate was then charged to a surface charge density +7 while the lower plate was charged to a surface charge density of - ? The net charge induced on the center plate is

0 
-?
\+?
-?/2
\+?/2

Answer 20

0

Question 21

If the distance between two charges is halved, the electrical force between the charges

is two times stronger
is two times weaker
is four times stronger
is four times weaker

Answer 21

is four times stronger

Question 22

The electric field at a point P that is r distance away from an infinitely long line of charge is

Directly proportional to the distance r
Directly proportional to the distance r^2
Inversely proportional to the distance r
Inversely proportional to the distance r^2

Answer 22

Inversely proportional to the distance r

Question 23

The electrical field produced by an infinite plane sheet of charge at a point P that is r distance away from the sheet is ____ from the sheet.

Directly proportional to the distance r
Directly proportional to the distance r^2
Inversely proportional to the distance r^2
Independent of the distance

Answer 23

Independent of the distance

Question 24

Electric field of a magnitude E=40.0 N/C is detected at r=5.00 m from it’s source, which is a point charge Q=1.11x10^7 C. What is the magnitude of an electric force that acts on an electron separated by R=5.0 m from Q ? (Hint: electron’s charge equals 1.602x10^-19 C)

6. 41 N/C
7. 408 N/C
8. 0 N
9. 408x10^-18 N
10. 41x10^-18 N

Answer 24

6.41x10^-18 N

Question 25

The potential decreases as one moves ____ of the electric field. in the same direction as in the opposite direction as non of the above

Answer 25

in the same direction as

Question 26

If the surface charge density of a uniformly charged disk is negative, the directions of the electric fields on both sides of the plane are _____ Away from the disk planes Toward the disk planes Random Electric fields on both sides of the disk cancels out

Answer 26

Toward the disk planes

Question 27

Qualitatively speaking... like electric charges attract one another opposite charges repel one another opposite electric charges annihilate one another charges never occur singly-they occur only as dipoles like electric charges repel one another

Answer 27

like electric charges repel one another

Question 28

Which one of the following quantities is a vector (quantity that has magnitude and direction)? Electric charge Energy Electric field Potential difference

Answer 28

Electric field

Question 29

The work required to move a unit positive electrical charge from one point in space to another equals potential difference (or voltage) between these two points. SI unit for potential difference (voltage) is called a volt and can be expressed as ``` Coulomb/joule newton/coulomb watt*second joule*coulomb joule/coulomb ```

Answer 29

joule/coulomb

Question 30

Which of the following statements is TRUE? A) the electric field internal to an aluminum ring is randomized B) the electric field internal to an aluminum ring is zero C) the electric field intensity inside an aluminum ring is greater than the intensity outside the ring D) the lines of force inside the ring were a continuation of the lines of force outside the ring E) the equipotential lines measured inside the ring represented the same voltages as outside the ring

Answer 30

B) the electric field internal to an aluminum ring is zero

Question 31

To measure the intensity of an electric field a(n) ____ is used. ``` electron proton positive test charge negative test charge neutron ```

Answer 31

positive test charge

Question 32

The electric field between oppositely charged plates is ____ if the plate separation is much smaller than the dimensions of the plates. Uniform Nonuniform Zero Directly proportional to the square of plate distance Inversely proportional to the square of plate distance

Answer 32

Uniform

Question 33

Between two point charges, lines of force of an electric field created by these charges can be mapped. By convention the lines of force originate on negative charges and terminate on positive charges originate on positive charges and terminate on negative charges cross one another at points of equal potential are respectively parallel to the corresponding map of equipotential lines form closed loops inside the respective charges

Answer 33

originate on positive charges and terminate on negative charges

Question 34

Electric field of a magnitude E=40.0 N/C is detected at r=5.0 m from it's source, which is a point charge Q which has a charge of ... (Hint: use k=9.0E9 N*m^2/(C^2)) 2. 41x10^7 C 1. 11x10^-7 mC 0. 000000111 C 1. 1x10^-7 C 2. 22x10^-8 C

Answer 34

1.1x10^-7 C

Question 35

Equipotentials are lines along which A) The electric field is constant in magnitude and direction. B) The electric charge is constant in magnitude and direction. C) a charge moving at constant speed requires that the maximum amount of work be done against electrical forces. D) a charge may be moved at constant speed without work against electrical forces. E) charges move by themselves.

Answer 35

D) a charge may be moved at constant speed without work against electrical forces.

Question 36

Let's place a test charge Q=7.0x10^-6 C into the region of space occupied by a constant electric field of 3.129x10^4 N/C. The field will act on a test charge with a force of a magnitude 4. 47x10^9 N 22. 4x10^6 J 0. 219 J 2. 19x10^-1 N 0. 22 N

Answer 36

0.22 N

Question 37

A uniform electric field of 2x10^5 N/C exists between two conductor plates separated by a distance of 15 cm. What is the voltage difference between them? 30000V 3000V 13333.33 133.33

Answer 37

30000V

Question 38

To detect the existence of a force field, an appropriate test particle of some kind is used. For example a ____ is used to detect the existence of a gravitational force field while a _____ is used to detect the existence of an electric field. ``` {test charge...compass} {test magnet...test charge} {compass...test mass} {test mass...test charge} {test mass...test magnet} ```

Answer 38

{test mass...test charge}

Question 39

A test charge (used in order to detect an electric field) must ``` produce a significant magnetic field alter the electric field of interest not alter the electric field of interest be an electron move in the direction which is perpendicular to the force line ```

Answer 39

not alter the electric field of interest

Question 40

Since a test charge at rest with respect to a static electric field experiences a well-determined force, one can observe that electric field lines of force ``` never intersect one another are everywhere parallel to the equipotential surface are everywhere parallel to each other sometimes interest one another always intersect one another ```

Answer 40

never intersect one another