Question 1

A charge Q1 = Q is positioned on the x axis at x = a.Where should a charge Q2 = 9Q be placed to produce a net electric force of zero on a charge placed at the origin?

Accepted Answer

A) at x = 2a 
B) at x = -2a 
C) at x = 3a 
D) at x = -3a 
E) at x = 4a 
A) at x = 2a 
B) at x = -2a 
C) at x = 3a 
D) at x = -3a 
E) at x = 4a

Question 2

In the figure the net electrostatic force on charge QA is zero.If QA = +1 nC,determine the magnitude of Q0 if position of QA is (+2a,-2a).

Accepted Answer

A) 4.24 nC 
B) 3.04 nC 
C) 6.80 nC 
D) 9.61 nC 
E) 2.15 nC 
A) 4.24 nC 
B) 3.04 nC 
C) 6.80 nC 
D) 9.61 nC 
E) 2.15 nC

Question 3

Two ions are placed on the x-axis.One has a charge of +e and is located at the origin.The other has a charge of -4e and is located at x = +d,where d > 0.Where on the x-axis could a third charge be placed such that the net electrostatic force on it caused by the other two charges is zero?

Accepted Answer

A) x = -2d 
B) x = -d 
C) x = +d 
D) x = +2d 
A) x = -2d 
B) x = -d 
C) x = +d 
D) x = +2d

Question 4

How many alpha particles are needed to produce a total charge of 2.5 * 10-12 C? (Hint: Each alpha particle contains two protons.)

Accepted Answer

A) 7.8 Million 
B) 1.6 * 10-19 
C) 2 
D) 839 
E) 4.2 * 1013 
A) 7.8 Million 
B) 1.6 * 10-19 
C) 2 
D) 839 
E) 4.2 * 1013

Question 5

Consider two protons placed near one another with no other objects close by.They would

Accepted Answer

A) accelerate away from each other. 
B) remain motionless. 
C) accelerate toward each other. 
D) be pulled together at constant speed. 
E) move away from each other at constant speed. 
A) accelerate away from each other. 
B) remain motionless. 
C) accelerate toward each other. 
D) be pulled together at constant speed. 
E) move away from each other at constant speed.

Question 6

An uncharged metal plate (P)is connected by a conductor to ground through a switch (S).The switch (S)is initially closed.A negative charge -Q is brought close to P without touching it and then the switch (S)is opened.After the switch (S)is open,the negative charge -Q is removed.After the negative charge -Q is removed,what is the charge on the plate (P)?

Accepted Answer

A) It is now positively charged. 
B) It is now negatively charged. 
C) It is still uncharged. 
D) It cannot be determined without knowing how much charge was on the metal plate P before switch S was closed. 
A) It is now positively charged. 
B) It is now negatively charged. 
C) It is still uncharged. 
D) It cannot be determined without knowing how much charge was on the metal plate P before switch S was closed.

Question 7

Two spheres carry electric charge,and a third charged sphere is now placed between the two charged spheres on a line connecting the two spheres' centers.If the result of the placement of the third charge is that there is no net electrostatic force on each of the two original spheres,what can be said?

Accepted Answer

A) The original spheres carried charges of opposite sign. 
B) The original spheres carried charges of the same sign. 
C) The original spheres carried charges of equal magnitude. 
D) The new charge is placed equidistant from each of the two original charges. 
E) None of the choices may be said with certainty. 
A) The original spheres carried charges of opposite sign. 
B) The original spheres carried charges of the same sign. 
C) The original spheres carried charges of equal magnitude. 
D) The new charge is placed equidistant from each of the two original charges. 
E) None of the choices may be said with certainty.

Question 8

Two charges of 1.6 * 10-3 C and 6.4 * 10-4 C are a distance of 5.1 m apart.What is the magnitude of the force (in N)acting between them?

Accepted Answer

A) 354 N 
B) 290 N 
C) 120 N 
D) 456 N 
E) 35 N 
A) 354 N 
B) 290 N 
C) 120 N 
D) 456 N 
E) 35 N

Question 9

What is the force on the -4  $\mu$C sphere?

Accepted Answer

A) 550 N,to the left 
B) 350 N,to the left 
C) 0 
D) 350 N,to the right 
E) 550 N to the right 
A) 550 N,to the left 
B) 350 N,to the left 
C) 0 
D) 350 N,to the right 
E) 550 N to the right

Question 10

Two point charges are placed on two of the corners of a triangle as shown.What magnitude of force would be felt by a 6.0 µC charge placed at the right angle?

Accepted Answer

A) 10 N 
B) 24 N 
C) 32 N 
D) 44 N 
E) 58 N 
A) 10 N 
B) 24 N 
C) 32 N 
D) 44 N 
E) 58 N

Question 11

Two charged objects are a distance 2.0 m apart.Object X has a charge 33.0 C and Object Y has 3.0 C.

Accepted Answer

A) The magnitude of electrostatic force on X is 11 times that on Y. 
B) The magnitude of electrostatic force on Y is 11 times that on X. 
C) The electrostatic force on X is the negative of that on Y. 
D) The electrostatic force on X is the same as that on Y. 
A) The magnitude of electrostatic force on X is 11 times that on Y. 
B) The magnitude of electrostatic force on Y is 11 times that on X. 
C) The electrostatic force on X is the negative of that on Y. 
D) The electrostatic force on X is the same as that on Y.

Question 12

Two point charges are placed on two of the corners of a triangle as shown.What magnitude of force would be felt by a 1.0 µC charge placed at the right angle?

Accepted Answer

A) 1.4 N 
B) 2.9 N 
C) 3.3 N 
D) 5.4 N 
E) 6.8 N 
A) 1.4 N 
B) 2.9 N 
C) 3.3 N 
D) 5.4 N 
E) 6.8 N

Question 13

Two equal masses of charge 36 nC each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5S1U1P1$\circ$S1S1P0with respect to each other.What is the mass of one of the two equal masses?

Accepted Answer

A) 8.1 g 
B) 15 g 
C) 4.1 g 
D) 3.6 g 
E) 6.7 g 
A) 8.1 g 
B) 15 g 
C) 4.1 g 
D) 3.6 g 
E) 6.7 g

Question 14

Two equal masses of charge 36 nC each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5S1U1P1$\circ$S1S1P0 with respect to each other.What is the tension in one of the strings?

Accepted Answer

A) 0.060 N 
B) 0.044 N 
C) 0.019 N 
D) 0.023 N 
E) 0.035 N 
A) 0.060 N 
B) 0.044 N 
C) 0.019 N 
D) 0.023 N 
E) 0.035 N

Question 15

Two charges of 0.5 C are placed at (0,1)and (1,0).A charge of -0.5 C is placed at (0,0).What is the direction of the force on a positive charge placed at (1,1)?

Accepted Answer

A) towards the origin 
B) towards (1,0) 
C) towards (0,1) 
D) away from the origin 
E) There is not enough information given to tell. 
A) towards the origin 
B) towards (1,0) 
C) towards (0,1) 
D) away from the origin 
E) There is not enough information given to tell.

Question 16

If you wish to lose weight,you may rub a balloon on your head.If you charge the balloon to a charge of q = -1.23µC,how much weight did you lose? The mass of an electron is 9.11 *10-31 kg.

Accepted Answer

A) 7.27 * 10-24 N 
B) 6.87 * 10-17 N 
C) 7.54 * 10-16 N 
D) 1.21 * 10-15 N 
E) 1.28 * 10-12 N 
A) 7.27 * 10-24 N 
B) 6.87 * 10-17 N 
C) 7.54 * 10-16 N 
D) 1.21 * 10-15 N 
E) 1.28 * 10-12 N

Question 17

What is the net charge of 1 mole (6.02 * 1023)of electrons?

Accepted Answer

A) -5.48 * 10-7 C 
B) 5.48 * 10-7 C 
C) -6.02 * 103 C 
D) -9.63 * 104 C 
E) 9.63 * 104 C 
A) -5.48 * 10-7 C 
B) 5.48 * 10-7 C 
C) -6.02 * 103 C 
D) -9.63 * 104 C 
E) 9.63 * 104 C

Question 18

Three electrons are located at the vertices of an equilateral triangle,one at each vertex.The length of one side of the triangle is 1.00 nm.What is the magnitude of the initial acceleration of each electron?

Accepted Answer

A) 2.52 * 1020 m/s2 
B) 3.57 * 1020 m/s2 
C) 4.38 * 1020 m/s2 
D) 5.05 * 1020 m/s2 
A) 2.52 * 1020 m/s2 
B) 3.57 * 1020 m/s2 
C) 4.38 * 1020 m/s2 
D) 5.05 * 1020 m/s2

Question 19

When a positively charged rod is brought near to an isolated neutral conductor without touching it,will the rod experience an attractive force,a repulsive force,or no force at all?

Accepted Answer

A) an attractive force 
B) a repulsive force 
C) no force at all 
A) an attractive force 
B) a repulsive force 
C) no force at all

Question 20

Three point charges are positioned on the x axis.If the charges and corresponding positions are -25.0 µC at x = 0.00 cm,-50.0 µC at x = 30.0 cm,and +100.0 µC at x = 80.0 cm,what is the magnitude of the electrostatic force on the -25.0 -µC charge?

Accepted Answer

A) 89.7 N 
B) 160 N 
C) 8.97 mN 
D) 16.0 mN 
E) 0 N 
A) 89.7 N 
B) 160 N 
C) 8.97 mN 
D) 16.0 mN 
E) 0 N

Exam 21: Electrostatics

A charge Q1 = Q is positioned on the x axis at x = a.Where should a charge Q2 = 9Q be placed to produce a net electric force of zero on a charge placed at the origin?

In the figure the net electrostatic force on charge QA is zero.If QA = +1 nC,determine the magnitude of Q0 if position of QA is (+2a,-2a).

Two ions are placed on the x-axis.One has a charge of +e and is located at the origin.The other has a charge of -4e and is located at x = +d,where d > 0.Where on the x-axis could a third charge be placed such that the net electrostatic force on it caused by the other two charges is zero?

How many alpha particles are needed to produce a total charge of 2.5 * 10-12 C? (Hint: Each alpha particle contains two protons.)

Consider two protons placed near one another with no other objects close by.They would

Two charges of 1.6 * 10-3 C and 6.4 * 10-4 C are a distance of 5.1 m apart.What is the magnitude of the force (in N)acting between them?

What is the force on the -4 μ\muμ C sphere?

Two point charges are placed on two of the corners of a triangle as shown.What magnitude of force would be felt by a 6.0 µC charge placed at the right angle?

Two charged objects are a distance 2.0 m apart.Object X has a charge 33.0 C and Object Y has 3.0 C.

Two point charges are placed on two of the corners of a triangle as shown.What magnitude of force would be felt by a 1.0 µC charge placed at the right angle?

Two equal masses of charge 36 nC each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5 ∘\circ∘ with respect to each other.What is the mass of one of the two equal masses?

Two equal masses of charge 36 nC each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5 ∘\circ∘ with respect to each other.What is the tension in one of the strings?

Two charges of 0.5 C are placed at (0,1)and (1,0).A charge of -0.5 C is placed at (0,0).What is the direction of the force on a positive charge placed at (1,1)?

If you wish to lose weight,you may rub a balloon on your head.If you charge the balloon to a charge of q = -1.23µC,how much weight did you lose? The mass of an electron is 9.11 *10-31 kg.

What is the net charge of 1 mole (6.02 * 1023)of electrons?

Three electrons are located at the vertices of an equilateral triangle,one at each vertex.The length of one side of the triangle is 1.00 nm.What is the magnitude of the initial acceleration of each electron?

When a positively charged rod is brought near to an isolated neutral conductor without touching it,will the rod experience an attractive force,a repulsive force,or no force at all?

Three point charges are positioned on the x axis.If the charges and corresponding positions are -25.0 µC at x = 0.00 cm,-50.0 µC at x = 30.0 cm,and +100.0 µC at x = 80.0 cm,what is the magnitude of the electrostatic force on the -25.0 -µC charge?

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Filters

A charge Q₁ = Q is positioned on the x axis at x = a.Where should a charge Q₂ = 9Q be placed to produce a net electric force of zero on a charge placed at the origin?

In the figure the net electrostatic force on charge Q_A is zero.If Q_A = +1 nC,determine the magnitude of Q₀ if position of Q_A is (+2a,-2a).

How many alpha particles are needed to produce a total charge of 2.5 * 10^-12 C? (Hint: Each alpha particle contains two protons.)

Two charges of 1.6 * 10^-3 C and 6.4 * 10^-4 C are a distance of 5.1 m apart.What is the magnitude of the force (in N)acting between them?

What is the force on the -4 $\mu$ C sphere? $What is the force on the -4 \mu C sphere?$

Two equal masses of charge 36 nC each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5^$\circ$with respect to each other.What is the mass of one of the two equal masses?

Two equal masses of charge 36 nC each are suspended at the end of two 1-m strings of negligible mass.The ropes make and angle of 5^$\circ$ with respect to each other.What is the tension in one of the strings?

If you wish to lose weight,you may rub a balloon on your head.If you charge the balloon to a charge of q = -1.23µC,how much weight did you lose? The mass of an electron is 9.11 *10^-31 kg.

What is the net charge of 1 mole (6.02 * 10²³)of electrons?