Question 1

Two point charges are 4 cm apart.They are moved to a new separation of 8 cm.By what factor does the resulting mutual force between them change?
A) 1/4
B) 2
C) 1/2
D) 4

Accepted Answer

The force between two point charges is inversely proportional to the square of the distance between them. Doubling the distance (from 4 cm to 8 cm) results in the force being reduced by a factor of 4 (1/2^2 = 1/4).

Question 2

Two identical spheres each carry a charge of −40.0 µC.The spheres are separated by a distance of 2.00 m.What is the electric force between the spheres? (k_e = 8.99 × 10⁹ N·m²/C²) A) 43.2 N (attractive) B) 14.4 N (repulsive) C) 3.60 N (repulsive) D) 7.19 N (attractive)

Accepted Answer

C

Question 3

A proton initially moves left to right long the x axis at a speed of 2.00 × 10³ m/s.It moves into an electric field,which points in the negative x direction,and travels a distance of 0.300 m before coming to rest.If the proton's mass and charge are 1.67 × 10−²⁷ kg and 1.60 × 10−¹⁹ C,respectively,what is the magnitude of the electric field? A) 13.9 N/C B) 0.0696 N/C C) 28.3 N/C D) 0.104 N/C

Accepted Answer

The initial kinetic energy of the proton is given by KE = 0.5mv^2, where m is the mass of the proton and v is its initial velocity. Plugging in the given values, we get KE = 1.11 × 10^-13 J.

As the proton moves through the electric field, it experiences a force given by F = qE, where q is the charge of the proton and E is the magnitude of the electric field. This force acts in the direction opposite to the proton's initial velocity, so it slows down the proton until it comes to rest.

The work done by the electric force on the proton is equal to the change in the proton's kinetic energy, since there are no other forces doing work on the proton. Therefore, we can write:

W = KE_final - KE_initial

where W = Fd is the work done by the electric force, and d is the distance traveled by the proton before it comes to rest. Solving for E, we get:

E = (F/d) = (KE_final - KE_initial)/qd

We know that KE_final = 0, since the proton comes to rest, so we can simplify the equation to:

E = KE_initial/qd

Plugging in the given values, we get:

E = (1.11 × 10^-13 J)/(1.60 × 10^-19 C × 0.300 m) ≈ 0.0696 N/C

Therefore, the answer is B: 0.0696 N/C.

Question 4

If two 1.0-C charges have a force between them of 1.0 N,what is their separation? A) 8.1 × 10¹⁹ m B) 1.0 m C) 9.5 × 10⁴ m D) 9.0 × 10¹⁰ m

Accepted Answer

Coulomb's Law states that the force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them. Using Coulomb's Law, we have:
F = k*q1*q2 / r^2
where F is the force between the charges, q1 and q2 are the charges, r is the distance between the charges, and k is Coulomb's constant. Solving for r, we get:
r = sqrt(k*q1*q2 / F)
Plugging in the given values, we get:
r = sqrt((9*10^9 N*m^2/C^2)*(1.0 C)*(1.0 C) / (1.0 N))
r = 9.5*10^-4 m
which is approximately equal to 9.5*10^-11 m or 0.95 nm. Therefore, the correct answer is C.

Question 5

The charge per unit length on an insulator is 6.2 μC/m.On a 2.0-m length of this material,what is the difference in the number of electrons and the number of protons? A) There are 7.8 × 10¹³ more electrons than protons. B) There are 7.8 × 10¹³more protons than electrons. C) There are 3.9 × 10¹³more protons than electrons. D) There are 3.9 × 10¹³more electrons than protons.

Accepted Answer

The answer of The charge per unit length on an...

Question 6

Two point charges,one q and the other -q,form a dipole separated by a distance 2L.A third charge Q is placed midway between these two charges.If the only charge that is negative is -q,what is the force on Q?
A)
 toward -q
B)
 toward q
C)
 toward -​q
D)
 toward q

Accepted Answer

The answer of Two point charges,one q and the other...

Question 7

An electron is sent at high speed toward a gold nucleus (charge +79e).What is the electrical force acting on the electron when it is 3.0 × 10−¹³ m away from the gold nucleus? (e = 1.6 × 10−¹⁹ C,k_e = 8.99 × 10⁹ N·m²/C²) A) 2.1 × 10−⁶ N B) 2.0 × 10−⁴ N C) 0.20 N D) 20 N

Accepted Answer

The answer of An electron is sent at high speed...

Question 8

If the distance between two point charges is quadrupled,the mutual force between them will be changed by what factor?
A) 8
B) 4
C) 1/16
D) 1/4

Accepted Answer

The mutual force between two point charges is inversely proportional to the square of the distance between them (Coulomb's Law). If the distance is quadrupled, the force is reduced by a factor of (4^2) = 16, so the force becomes 1/16 of the original.

Question 9

Two point charges,separated by 15 cm,have charge values of +2.0 µC and −4.0 µC,respectively.What is the value of the mutual force between them? (k_e = 8.99 × 10⁹ N⋅m²/C²) A) 8.0 × 10−¹² N B) 3.6 × 10−⁸ N C) 320 N D) 3.2 N

Accepted Answer

The answer of Two point charges,separated by 15 cm,have charge...

Question 10

Two point charges are separated by 10.0 cm and have charges of +1.00 µC and −1.00 µC,respectively.What is the electric field at a point midway between the two charges? (k_e = 8.99 × 10⁹ N·m²/C²) A) 14.4 × 10⁶ N/C B) zero C) 28.8 × 10⁶ N/C D) 7.19 × 10⁶ N/C

Accepted Answer

The answer of Two point charges are separated by 10.0...

Question 11

Two point charges are placed along a horizontal axis with the following values and positions: +3.0 µC at x = 0 cm and −6.0 µC at x = 20 cm.At what point along the x axis is the electric field zero?
A) 8.0 cm
B) −48 cm
C) −38 cm
D) −69 cm

Accepted Answer

The answer of Two point charges are placed along a...

Question 12

Charges of 4.0 µC and −6.0 µC are placed at two corners of an equilateral triangle with sides of 0.20 m.At the third corner,what is the electric field magnitude created by these two charges? (k_e = 8.99 × 10⁹ N·m²/C²) A) 3.1 × 10⁶ N/C B) 1.2 × 10⁶ N/C C) 4.8 × 10⁶ N/C D) 4.5 × 10⁶ N/C

Accepted Answer

The answer of Charges of 4.0 µC and −6.0 µC...

Question 13

An electron with a charge value of 1.6 × 10−¹⁹ C is moving in the presence of an electric field of 300 N/C.What force does the electron experience? A) 2.3 × 10−²² N B) 4.8 × 10−¹⁷ N C) 6.4 × 10−¹⁷ N D) 1.9 × 10−²¹ N

Accepted Answer

The force experienced by an electron in the presence of an electric field is given by F = qE, where q is the charge of the electron and E is the electric field strength. Substituting the given values, we get:
F = (1.6 × 10^-19C) (300 N/C)
F = 4.8 × 10^-17N
Therefore, the answer is B, 4.8 × 10^-17N.

Question 14

Object A has a charge q on it,object B has a charge q on it,and object C has a charge 2q on it.These charges are arranged,one each,at the vertices of an equilateral triangle.Which charge has the greatest magnitude electric force on it?
A) A
B) C
C) B
D) All have equal magnitude forces on them.

Accepted Answer

The magnitude of the electric force between two charges is proportional to the product of the charges and inversely proportional to the square of the distance between them. In this case, the distance between any two charges is the same, so the magnitude of the force depends only on the product of the charges. Since object C has the largest charge (2q), it will experience the greatest magnitude force. Therefore, choice B is the best answer.

Question 15

A metallic object holds a charge of −2.9 × 10−⁵ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. ) A) 1.8 × 10¹⁴ B) 2.4 × 10¹³ C) 6.1 × 10¹³ D) 4.2 × 10¹⁴

Accepted Answer

The total number of electrons is equal to the charge on the object divided by the charge of a single electron. So, the number of electrons is:```n = Q / e = (-2.9 × 10^-5 C) / (1.6 × 10^-19 C) = 1.8 × 10^14 electrons```

Question 16

If the size of the charge value is tripled for one of two point charges maintained at a constant separation,the mutual force between them will be changed by what factor?
A) 3.0
B) 1/9
C) 9.0
D) 0.33

Accepted Answer

The answer of If the size of the charge value...

Question 17

An electron with a speed of 2.0 × 10⁶ m/s moves into a uniform electric field of 325 N/C that is parallel to the electron's motion.How long does it take to bring the electron to rest? (me = 9.11 × 10−³¹ kg,e = 1.6 × 10−¹⁹ C) A) 3.5 × 10−⁸ s B) 2.3 × 10−⁶ s C) 2.3 × 10−⁸ s D) 1.2 × 10−⁷ s

Accepted Answer

The answer of An electron with a speed of 2.0...

Question 18

Two point charges,one ​q and the other -q,form a dipole separated by a distance d.A third charge Q is placed midway between these two charges.If the distance between q and -q is then doubled with the Q staying midway between the other two,what happens to the force on Q?
A) It halves.
B) It reduces by a factor of 8.
C) It stays the same.
D) It quarters.

Accepted Answer

The force between q and -q is given by Coulomb's Law as F = kq^2/d^2 where k is the Coulomb constant. When the distance between q and -q is doubled, the force between them decreases by a factor of 4. However, since charge Q is equidistant from q and -q, the distance between Q and each of the charges remains the same. Therefore, the force on Q due to each charge still remains the same. Since the two forces acting on Q are in opposite directions and are of equal magnitude, they cancel each other out. Thus, the net force on Q remains the same, which means the answer is D, it quarters.

Question 19

About how many electrons are in 0.3 gram of water (H₂O)? A) 10²³ B) 10²¹ C) 10²⁵ D) 10¹⁹

Accepted Answer

0.3 gram of water contains 0.3/18 moles of water, which is 1.67 x 10^-2 moles. Each water molecule contains 10 electrons, so 1.67 x 10^-2 moles of water contains 1.67 x 10^-2 moles x 10 electrons/mole = 1.67 x 10^-1 moles of electrons. 1.67 x 10^-1 moles of electrons is equal to 1.00 x 10^23 electrons.

Question 20

Two point charges each have a value of 30.0 mC and are separated by a distance of 3.00 cm.What is the electric field midway between the two charges? (k_e = 8.99 × 10⁹ N·m²/C²) A) 40.5 × 10⁷ N/C B) 20.3 × 10⁷ N/C C) zero D) 10.1 × 10⁷ N/C

Accepted Answer

The electric field midway between the two charges will be zero because the electric fields produced by the two charges cancel each other out at that point. Therefore, the correct answer is C (zero).

Quiz 17: Current and Resistance Electric Current: Part A

Two point charges are 4 cm apart.They are moved to a new separation of 8 cm.By what factor does the resulting mutual force between them change?

Two identical spheres each carry a charge of −40.0 µC.The spheres are separated by a distance of 2.00 m.What is the electric force between the spheres? (k_e = 8.99 × 10⁹ N·m²/C²)

If two 1.0-C charges have a force between them of 1.0 N,what is their separation?

The charge per unit length on an insulator is 6.2 μC/m.On a 2.0-m length of this material,what is the difference in the number of electrons and the number of protons?

Two point charges,one q and the other -q,form a dipole separated by a distance 2L.A third charge Q is placed midway between these two charges.If the only charge that is negative is -q,what is the force on Q?

An electron is sent at high speed toward a gold nucleus (charge +79e) .What is the electrical force acting on the electron when it is 3.0 × 10−¹³ m away from the gold nucleus? (e = 1.6 × 10−¹⁹ C,k_e = 8.99 × 10⁹ N·m²/C²)

If the distance between two point charges is quadrupled,the mutual force between them will be changed by what factor?

Two point charges,separated by 15 cm,have charge values of +2.0 µC and −4.0 µC,respectively.What is the value of the mutual force between them? (k_e = 8.99 × 10⁹ N⋅m²/C²)

Two point charges are separated by 10.0 cm and have charges of +1.00 µC and −1.00 µC,respectively.What is the electric field at a point midway between the two charges? (k_e = 8.99 × 10⁹ N·m²/C²)

Two point charges are placed along a horizontal axis with the following values and positions: +3.0 µC at x = 0 cm and −6.0 µC at x = 20 cm.At what point along the x axis is the electric field zero?

Charges of 4.0 µC and −6.0 µC are placed at two corners of an equilateral triangle with sides of 0.20 m.At the third corner,what is the electric field magnitude created by these two charges? (k_e = 8.99 × 10⁹ N·m²/C²)

An electron with a charge value of 1.6 × 10−¹⁹ C is moving in the presence of an electric field of 300 N/C.What force does the electron experience?

Object A has a charge q on it,object B has a charge q on it,and object C has a charge 2q on it.These charges are arranged,one each,at the vertices of an equilateral triangle.Which charge has the greatest magnitude electric force on it?

A metallic object holds a charge of −2.9 × 10−⁵ C.What total number of electrons does this represent? (e = 1.6 × 10−¹⁹ C is the magnitude of the electronic charge. )

If the size of the charge value is tripled for one of two point charges maintained at a constant separation,the mutual force between them will be changed by what factor?

An electron with a speed of 2.0 × 10⁶ m/s moves into a uniform electric field of 325 N/C that is parallel to the electron's motion.How long does it take to bring the electron to rest? (me = 9.11 × 10−³¹ kg,e = 1.6 × 10−¹⁹ C)

Two point charges,one q and the other -q,form a dipole separated by a distance d.A third charge Q is placed midway between these two charges.If the distance between q and -q is then doubled with the Q staying midway between the other two,what happens to the force on Q?

About how many electrons are in 0.3 gram of water (H₂O) ?

Two point charges each have a value of 30.0 mC and are separated by a distance of 3.00 cm.What is the electric field midway between the two charges? (k_e = 8.99 × 10⁹ N·m²/C²)

Quiz 17: Current and Resistance Electric Current: Part A

Two point charges are 4 cm apart.They are moved to a new separation of 8 cm.By what factor does the resulting mutual force between them change?

Two identical spheres each carry a charge of −40.0 µC.The spheres are separated by a distance of 2.00 m.What is the electric force between the spheres? (ke = 8.99 × 109 N·m2/C2)

If two 1.0-C charges have a force between them of 1.0 N,what is their separation?

The charge per unit length on an insulator is 6.2 μC/m.On a 2.0-m length of this material,what is the difference in the number of electrons and the number of protons?

Two point charges,one q and the other -q,form a dipole separated by a distance 2L.A third charge Q is placed midway between these two charges.If the only charge that is negative is -q,what is the force on Q?

An electron is sent at high speed toward a gold nucleus (charge +79e) .What is the electrical force acting on the electron when it is 3.0 × 10−13 m away from the gold nucleus? (e = 1.6 × 10−19 C,ke = 8.99 × 109 N·m2/C2)

If the distance between two point charges is quadrupled,the mutual force between them will be changed by what factor?

Two point charges,separated by 15 cm,have charge values of +2.0 µC and −4.0 µC,respectively.What is the value of the mutual force between them? (ke = 8.99 × 109 N⋅m2/C2)

Two point charges are separated by 10.0 cm and have charges of +1.00 µC and −1.00 µC,respectively.What is the electric field at a point midway between the two charges? (ke = 8.99 × 109 N·m2/C2)

Two point charges are placed along a horizontal axis with the following values and positions: +3.0 µC at x = 0 cm and −6.0 µC at x = 20 cm.At what point along the x axis is the electric field zero?

Charges of 4.0 µC and −6.0 µC are placed at two corners of an equilateral triangle with sides of 0.20 m.At the third corner,what is the electric field magnitude created by these two charges? (ke = 8.99 × 109 N·m2/C2)

An electron with a charge value of 1.6 × 10−19 C is moving in the presence of an electric field of 300 N/C.What force does the electron experience?