Question 1

Consider the field lines of the electric dipole in this diagram, relative to the w-axis and the z-axis.  In which direction does the electric field point where the two axes intersect?

Accepted Answer

The answer of Consider the field lines of the electric...

Question 2

Consider the horizontal parallel plates. The upper plate has a voltage difference of 30 V with the lower plate, and they are separated by 3 cm. You move the two plates carefully to a separation of 4 cm. What is the strength of the electric field between the plates?

Accepted Answer

The electric field strength between two plates is given by the voltage difference divided by the separation distance. Initially, the electric field strength is $ \frac{30\,V}{3\,cm} = \frac{30\,V}{0.03\,m} = 1000\,V/m $. When the separation is increased to 4 cm (or 0.04 m), the electric field strength becomes $ \frac{30\,V}{0.04\,m} = 750\,V/m $.

Question 3

Two charges are shown below. What is the direction of the electric field at the indicated point?

Accepted Answer

The answer of Two charges are shown below. What is...

Question 4

The most common form of lightning strike from a cloud to the ground involves negative charge moving from the cloud to the ground. Just before a lightning strike,

Accepted Answer

The electric field must point toward the sky just before a lightning strike because negative charge is moving from the cloud to the ground. This creates an intense electric field pointing from the cloud to the ground, which is necessary for the lightning to occur. Additionally, choice B and C are incorrect because the potential energy of the electrons in the cloud must be high and the potential near the cloud must be lower in order for the lightning strike to occur. Choice D is also incorrect because there are charges on the ground, just fewer than in the cloud.

Question 5

Two charges of equal magnitude but opposite sign are 10 cm apart. The potential is largest

Accepted Answer

The answer of Two charges of equal magnitude but opposite...

Question 6

As a given thundercloud's base elevation gets lower and lower, the possibility of lightning strike

Accepted Answer

As the cloud gets closer to the ground, the distance between the cloud and the ground decreases, which increases the electric field strength. This, in turn, increases the likelihood of a lightning strike.

Question 7

A positive charge is fixed at the origin. A negative charge is moved along the x-axis from x = 50 cm to x = 10 cm. The potential energy of the negative charge

Accepted Answer

The potential energy of a pair of point charges is given by the equation PE = kqQ/r, where k is a constant, q and Q are the charges of the two particles, and r is the distance between them. As the negative charge is moved closer to the positive charge, the distance between them decreases, and so does the potential energy. Therefore, the potential energy of the negative charge decreases as it moves from x = 50 cm to x = 10 cm.

Question 8

If the plates of a charged parallel plate capacitor were moved further apart, the potential energy of each of the charges on the capacitor would

Accepted Answer

The potential energy of each charge on a capacitor is proportional to the distance between the plates. As the plates are moved further apart, the potential energy of each charge will increase. This can be seen from the equation for the potential energy of a capacitor: U = (1/2)CV^2, where C is the capacitance and V is the voltage. Since C is constant for a given capacitor, increasing the distance between the plates (and thus the electric field strength) increases the voltage V, which in turn increases the potential energy U.

Question 9

If two metal balls each have a charge of -10^-6 C and the repulsive force between them is 1 N, how far apart are they? (Coulomb's constant is k=9.0 $\times$10⁹ N^.m²/C².)

Accepted Answer

The formula for Coulomb's law is:

F = k * (q1 * q2) / r^2

where F is the force, q1 and q2 are the charges, r is the distance between the charges, and k is Coulomb's constant.

We can rearrange the formula to solve for r:

r = sqrt(k * (q1 * q2) / F)

Plugging in the given values:

r = sqrt((9.0 * 10^9 N*m^2/C^2) * ((-10^-6 C) * (-10^-6 C)) / 1 N)

r = 9.5 cm

Therefore, the answer is C) 9.5 cm.

Question 10

Two equal charges repel one another with a force of 4.0$\times$ 10^-4 N when they are 10 cm apart. (Coulomb's constant is k=9.0$\times$ 10⁹ N^.m²/C².)If they are moved until the separation is 5 cm, the repulsive force will be

Accepted Answer

The force between two charges is inversely proportional to the square of the distance between them, so when the distance is halved (i.e. goes from 10 cm to 5 cm), the force will increase by a factor of 4 (2 squared). Therefore, the repulsive force will be 16 times greater, which is 16 N.

Question 11

When you shuffle your feet on a carpet on a dry day, you can accumulate a charge. The fact that you accumulate a charge means that the carpet is

Accepted Answer

Insulators, such as carpets, can hold a charge because the electrons cannot move easily through them. If the carpet were a conductor, the charge would immediately disperse, and no charge could accumulate on your body.

Question 12

Refer to the dipole in the z, w coordinate system above. Consider the electric field at a point $\degree$ out on the z-axis, above and to the right of the intersection of the axes. In which direction does the electric field point at point $\degree$?

Accepted Answer

The answer of Refer to the dipole in the z,...

Question 13

You have a pair of horizontal parallel plates, with the positive plate above and the negative plate below. How will the lines of constant potential be arranged in this perspective?

Accepted Answer

The lines of constant potential will be arranged horizontally because the electric field is perpendicular to the plates and the potential is constant along a horizontal plane between the two plates. Additionally, the charge distribution in this situation does not have spherical symmetry, so option A is incorrect. Option C is incorrect because the potential difference is parallel to the plates, so there is no vertical component to the potential.

Question 14

The unit for electric field, N/C, can be written equivalently as

Accepted Answer

The electric field is defined as the force per unit charge experienced by a test charge placed in the field. This can be expressed as E = F/Q. Using the equation for electric potential, V = W/Q, where W is the work done in moving the charge against the electrostatic force, and taking the negative gradient of the potential gives the electric field as E = -dV/dx. Therefore, the units of electric field are N/C, which can also be written as V/m.

Question 15

A point charge creates the electric field shown. At which of the points would the potential energy of a positive test charge have the largest value?

Accepted Answer

The answer of A point charge creates the electric field...

Question 16

A charged comb attracts bits of neutral dust in the air. This happens because

Accepted Answer

The dust becomes polarized when a charged comb is brought near it, causing the dust particles to be attracted to the comb due to the induced charges on them.

Question 17

A capacitor consisting of two separated parallel horizontal plates has a uniform electric field directed upward. If a negative charge is placed exactly midway between the two plates, it will

Accepted Answer

The electric field lines run from the positive to the negative plate, so a negative charge will be accelerated in the direction opposite to the field lines, which is downward.

Question 18

A capacitor consisting of two parallel plates separated by 2.0 cm has a potential of 40 V on the top plate and a potential of 0 V on the bottom plate. The electric field in the middle is

Accepted Answer

The electric field (E) between two parallel plates is given by E = V/d, where V is the potential difference and d is the separation between the plates. Here, V = 40 V and d = 2.0 cm = 0.02 m. Thus, E = 40 V / 0.02 m = 2000 N/C. The direction is from the positive to the negative plate, hence downward.

Question 19

Imagine four equal positive charges, q, placed on points of a circle of radius r at the 3, 6, 9, and 12 o'clock positions. Coulomb's constant is k. The magnitude of the electric field at the center of the circle is given by

Accepted Answer

The electric field at the center due to each charge will be directed radially outward or inward, and since the charges are equal and symmetrically placed, the fields due to each charge will cancel each other out. Therefore, the net electric field at the center of the circle is zero.

Question 20

Three equal negative charges are placed at three of the four corners of a square. The direction of the electric field at the remaining corner of the square is

Accepted Answer

Since the charges are negative, the electric field points toward each charge. Therefore, at the remaining corner of the square, the electric fields from the two adjacent charges cancel each other out along the sides of the square. The only remaining electric field is along the line connecting this corner with the opposite corner, and toward that corner.

Quiz 12: Electrostatic Phenomena

Consider the horizontal parallel plates. The upper plate has a voltage difference of 30 V with the lower plate, and they are separated by 3 cm. You move the two plates carefully to a separation of 4 cm. What is the strength of the electric field between the plates?

Two charges are shown below. What is the direction of the electric field at the indicated point?

The most common form of lightning strike from a cloud to the ground involves negative charge moving from the cloud to the ground. Just before a lightning strike,

Two charges of equal magnitude but opposite sign are 10 cm apart. The potential is largest

As a given thundercloud's base elevation gets lower and lower, the possibility of lightning strike

A positive charge is fixed at the origin. A negative charge is moved along the x-axis from x = 50 cm to x = 10 cm. The potential energy of the negative charge

If the plates of a charged parallel plate capacitor were moved further apart, the potential energy of each of the charges on the capacitor would

If two metal balls each have a charge of -10^-6 C and the repulsive force between them is 1 N, how far apart are they? (Coulomb's constant is k=9.0 $\times$ 10⁹ N^.m²/C².)

Two equal charges repel one another with a force of 4.0 $\times$ 10^-4 N when they are 10 cm apart. (Coulomb's constant is k=9.0 $\times$ 10⁹ N^.m²/C².) If they are moved until the separation is 5 cm, the repulsive force will be

When you shuffle your feet on a carpet on a dry day, you can accumulate a charge. The fact that you accumulate a charge means that the carpet is

Refer to the dipole in the z, w coordinate system above. Consider the electric field at a point $\degree$ out on the z-axis, above and to the right of the intersection of the axes. In which direction does the electric field point at point $\degree$ ?

You have a pair of horizontal parallel plates, with the positive plate above and the negative plate below. How will the lines of constant potential be arranged in this perspective?

The unit for electric field, N/C, can be written equivalently as

A point charge creates the electric field shown. At which of the points would the potential energy of a positive test charge have the largest value?

A charged comb attracts bits of neutral dust in the air. This happens because

A capacitor consisting of two separated parallel horizontal plates has a uniform electric field directed upward. If a negative charge is placed exactly midway between the two plates, it will

A capacitor consisting of two parallel plates separated by 2.0 cm has a potential of 40 V on the top plate and a potential of 0 V on the bottom plate. The electric field in the middle is

Imagine four equal positive charges, q, placed on points of a circle of radius r at the 3, 6, 9, and 12 o'clock positions. Coulomb's constant is k. The magnitude of the electric field at the center of the circle is given by

Three equal negative charges are placed at three of the four corners of a square. The direction of the electric field at the remaining corner of the square is

Quiz 12: Electrostatic Phenomena

Consider the field lines of the electric dipole in this diagram, relative to the w-axis and the z-axis. In which direction does the electric field point where the two axes intersect?

Consider the horizontal parallel plates. The upper plate has a voltage difference of 30 V with the lower plate, and they are separated by 3 cm. You move the two plates carefully to a separation of 4 cm. What is the strength of the electric field between the plates?

Two charges are shown below. What is the direction of the electric field at the indicated point?

The most common form of lightning strike from a cloud to the ground involves negative charge moving from the cloud to the ground. Just before a lightning strike,

Two charges of equal magnitude but opposite sign are 10 cm apart. The potential is largest

As a given thundercloud's base elevation gets lower and lower, the possibility of lightning strike

A positive charge is fixed at the origin. A negative charge is moved along the x-axis from x = 50 cm to x = 10 cm. The potential energy of the negative charge

If the plates of a charged parallel plate capacitor were moved further apart, the potential energy of each of the charges on the capacitor would

If two metal balls each have a charge of -10-6 C and the repulsive force between them is 1 N, how far apart are they? (Coulomb's constant is k=9.0 ×\times× 109 N.m2/C2.)

Two equal charges repel one another with a force of 4.0 ×\times× 10-4 N when they are 10 cm apart. (Coulomb's constant is k=9.0 ×\times× 109 N.m2/C2.) If they are moved until the separation is 5 cm, the repulsive force will be

When you shuffle your feet on a carpet on a dry day, you can accumulate a charge. The fact that you accumulate a charge means that the carpet is

Refer to the dipole in the z, w coordinate system above. Consider the electric field at a point °\degree° out on the z-axis, above and to the right of the intersection of the axes. In which direction does the electric field point at point °\degree° ?

You have a pair of horizontal parallel plates, with the positive plate above and the negative plate below. How will the lines of constant potential be arranged in this perspective?

The unit for electric field, N/C, can be written equivalently as

A point charge creates the electric field shown. At which of the points would the potential energy of a positive test charge have the largest value?

A charged comb attracts bits of neutral dust in the air. This happens because

A capacitor consisting of two separated parallel horizontal plates has a uniform electric field directed upward. If a negative charge is placed exactly midway between the two plates, it will

A capacitor consisting of two parallel plates separated by 2.0 cm has a potential of 40 V on the top plate and a potential of 0 V on the bottom plate. The electric field in the middle is

Imagine four equal positive charges, q, placed on points of a circle of radius r at the 3, 6, 9, and 12 o'clock positions. Coulomb's constant is k. The magnitude of the electric field at the center of the circle is given by

Three equal negative charges are placed at three of the four corners of a square. The direction of the electric field at the remaining corner of the square is

If two metal balls each have a charge of -10^-6 C and the repulsive force between them is 1 N, how far apart are they? (Coulomb's constant is k=9.0 $\times$ 10⁹ N^.m²/C².)

Two equal charges repel one another with a force of 4.0 $\times$ 10^-4 N when they are 10 cm apart. (Coulomb's constant is k=9.0 $\times$ 10⁹ N^.m²/C².) If they are moved until the separation is 5 cm, the repulsive force will be

Refer to the dipole in the z, w coordinate system above. Consider the electric field at a point $\degree$ out on the z-axis, above and to the right of the intersection of the axes. In which direction does the electric field point at point $\degree$ ?