Question 1

Positive charge Q is uniformly distributed on a semicircular rod.What is the direction of the electric field at point P, the center of the semicircle? 
A)" $\uparrow$ "
B)" $\downarrow$ "
C)" $\leftarrow$ "
D)" $\rightarrow$ "
E) ""

Accepted Answer

The answer of Positive charge Q is uniformly distributed on...

Question 2

Two point particles, one with charge +8 *10^-9 C and the other with charge-2 *0 10^-9 C, are separated by 4 m.The electric field midway between them is: A)9 * 10⁹N/C B)13,500 N/C C)135,000 N/C D)36 * 10^-9N/C E)22.5 N/C

Accepted Answer

The answer of Two point particles, one with charge +8...

Question 3

An electric dipole consists of a particle with a charge of +6 * 10^-6 C at the origin and a particle with a charge of -6 * 10^-6 C on the x axis at x = 3 * 10^-3 m.Its dipole moment is: A)1.8 * 10^-8 C.m, in the positive x direction B)1.8 * 10^-8 C.m, in the negative x direction C)0 C.m, because the net charge is 0 D)1.8 * 10^-8 C.m, in the positive y direction E)1.8 * 10^-8 C.m, in the negative y direction

Accepted Answer

The answer of An electric dipole consists of a particle...

Question 4

A charged particle is placed in an electric field that varies with location.No force is exerted on this charge: A)at locations where the electric field is zero B)at locations where the electric field strength is 1/(1.6 * 10^-19)N/C C)if the particle is moving along a field line D)if the particle is moving perpendicular to a field line E)if the field is caused by an equal amount of positive and negative charge

Accepted Answer

A charged particle placed in an electric field experiences a force given by F=qE, where q is the charge of the particle and E is the electric field strength. Therefore, if the electric field strength is zero (option A), the particle will not experience any force and will remain stationary. Option B gives a specific value of electric field strength, which may or may not be zero depending on the situation. Option C is incorrect because the particle's motion along a field line does not necessarily mean that it will not experience a force. Option D is also incorrect because if the particle is moving perpendicular to a field line, it will experience a force that is perpendicular to its velocity, resulting in curvilinear motion. Option E is also incorrect because the net effect of a combination of positive and negative charges is the electric field that is produced. If the electric field strength at a point is zero, it means that the net effect of the positive and negative charges cancel each other out at that point.

Question 5

Two point particles, with the same charge, are located at two vertices of an equilateral triangle.A third charged particle is placed so the electric field at the third vertex is zero.The third particle must:
A)be on the perpendicular bisector of the line joining the first two charges
B)be on the line joining the first two charges
C)be identical to the first two charges
D)have the same magnitude as the first two charges but may have a different sign
E)be at the center of the triangle

Accepted Answer

The answer of Two point particles, with the same charge,...

Question 6

The diagram shows two identical particles, each with positive charge Q.The electric field at point P on the perpendicular bisector of the line joining them is: 
A)" $\uparrow$ "
B)" $\downarrow$ "
C)" $\rightarrow$ "
D)" $\leftarrow$ "
E)zero

Accepted Answer

The answer of The diagram shows two identical particles, each...

Question 7

A total charge of 6.3 *10^-8 C is distributed uniformly throughout a 2.7-cm radius sphere.The volume charge density is: A)3.7 * 10^-7 C/m³ B)6.9 *10^-6 C/m³ C)6.9 *10^-6 C/m² D)2.5* 10^-4 C/m³ E)7.6 *10^-4 C/m³

Accepted Answer

The answer of A total charge of 6.3 *10^-8 C...

Question 8

An electric dipole consists of two charges, ±2.5 µC, separated by 1.0 x 10^-4 m and centered on the origin.If the dipole is oriented along the x axis, what is the electric field at x = 15 cm? A)0 N/C B)100 N/C C)200 N/C D)670 N/C E)1300 N/C

Accepted Answer

The answer of An electric dipole consists of two charges,...

Question 9

A disk with a uniform positive surface charge density lies in the x-y plane, centered on the origin.Along the positive z axis, the direction of the electric field is:
A)in the +z direction
B)in the -z direction
C)in the +x direction
D)in the +y direction
E)there is no field along the positive z axis

Accepted Answer

According to Gauss's law, the electric field due to a uniformly charged disk along its normal axis is given by E = σ/(2ε₀), where σ is the surface charge density and ε₀ is the permittivity of free space. Since the disk has a positive surface charge density, the electric field points away from the disk along the positive z axis, i.e., in the +z direction.

Question 10

A cylinder has a radius of 2.1 cm and a length of 8.8 cm.Total charge 6.1 *10^-7 C is distributed uniformly throughout.The volume charge density is: A)7.4 * 10^-11 C/m³ B)5.3 *10^-5 C/m³ C)5.3 *10^-5 C/m² D)8.5 * 10^-4 C/m³ E)5.0 *10^-3 C/m³

Accepted Answer

The answer of A cylinder has a radius of 2.1...

Question 11

Two point charges are arranged as shown.In which region could a third charge +1 C be placed so that the net electrostatic force on it is zero? 
A)I only
B)I and II only
C)III only
D)I and III only
E)II only

Accepted Answer

The answer of Two point charges are arranged as shown.In...

Question 12

A disk with a uniform positive surface charge density lies in the x-y plane, centered on the origin.The disk contains 2.5 x 10^-6 C/m² of charge, and is 7.5 cm in radius.What is the electric field at z = 15 cm? A)30 N/C B)300 N/C C)3000 N/C D)3.0 x 10⁴ N/C E)3.0 x 10⁷ N/C

Accepted Answer

The electric field of a disk with uniform surface charge density is given by:$$E = \frac{\sigma}{2\epsilon_0} \left ( 1 - \frac{z}{\sqrt{z^2 + R^2}} ight )$$where:$$\sigma$$ is the surface charge density$$\epsilon_0$$ is the permittivity of free space$$z$$ is the distance from the center of the disk to the point where the electric field is being calculated$$R$$ is the radius of the diskPlugging in the given values, we get:$$E = \frac{2.5 	imes 10^{-6} C/m^2}{2(8.85 	imes 10^{-12} C^2/Nm^2)} \left ( 1 - \frac{0.15 m}{\sqrt{0.15^2 m^2 + 0.075^2 m^2}} ight )$$$$E = 3.0 	imes 10^4 N/C$$

Question 13

Comparing the field of a single point charge with the field of an electric dipole,
A)the field of the point charge decreases more rapidly with distance
B)the field of the point charge decreases less rapidly with distance
C)the field of the point charge decreases more rapidly with distance but only along the dipole axis
D)the field of the point charge decreases less rapidly with distance but only perpendicular to the dipole axis
E)the fields decrease equally rapidly with distance

Accepted Answer

The field of a single point charge decreases as the inverse square of the distance from the charge (1/r^2), whereas the field of an electric dipole decreases more rapidly, as the inverse cube of the distance from the dipole's center (1/r^3) along any direction. Therefore, the field of the point charge decreases less rapidly with distance compared to the dipole field.

Question 14

A spherical shell has an inner radius of 3.7 cm and an outer radius of 4.5 cm.If charge is distributed uniformly throughout the shell with a volume density of 6.1 *10^-4 C/m³ the total charge is: A)1.0 *10^-7 C B)1.3 *10^-7 C C)2.0 * 10^-7 C D)1.7 *10^-⁶ C E)5.0 * 10^-⁶ C

Accepted Answer

The total charge is the volume of the shell multiplied by the charge density. The volume of a spherical shell is given by V = (4/3)π(R2 - r2), where R is the outer radius and r is the inner radius. The charge density is given by ρ = Q/V, where Q is the total charge. Substituting these expressions into the equation for the total charge, we get:Q = ρV = ρ(4/3)π(R2 - r2)= (6.1 × 10^-4 C/m3)(4/3)π[(4.5 cm)2 - (3.7 cm)2]= 1.0 × 10^-7 C

Question 15

The electric field due to a uniform distribution of charge on a spherical shell is zero:
A)everywhere
B)nowhere
C)only at the center of the shell
D)only inside the shell
E)only outside the shell

Accepted Answer

The electric field due to a uniform distribution of charge on a spherical shell is zero only inside the shell, according to Gauss's law. This is because the electric field lines do not penetrate into the enclosed space, effectively canceling out any net electric field within the shell.

Question 16

Positive charge +Q is uniformly distributed on the upper half of a semicircular rod and negative charge -Q is uniformly distributed on the lower half.What is the direction of the electric field at point P, the center of the semicircle? 
A)" $\uparrow$ "
B)"  $\downarrow$ "
C)" $\leftarrow$ "
D)" $\rightarrow$ "
E) ""

Accepted Answer

At point P, the electric field due to the upper half of the semicircular rod is directed downwards and the electric field due to the lower half of the semicircular rod is directed upwards. The magnitudes of these fields are equal due to the uniform charge distribution. Therefore, the net electric field at point P is directed upwards, perpendicular to the plane of the semicircle. Therefore, the correct choice is B, which shows the electric field pointing upwards.

Question 17

Two charged point particles are located at two vertices of an equilateral triangle and the electric field is zero at the third vertex.We conclude:
A)the two particles have charges with opposite signs and the same magnitude
B)the two particles have charges with opposite signs and different magnitudes
C)the two particles have identical charges
D)the two particles have charges with the same sign but different magnitudes
E)at least one other charged particle is present

Accepted Answer

The answer of Two charged point particles are located at...

Question 18

An electric dipole consists of a particle with a charge of +6 * 10^-6 C at the origin and a particle with a charge of -6*10^-6 C on the x axis at x = 3 *10^-3 m.The direction of the electric field due to the dipole at points on the x axis is: A)in the positive x direction B)in the negative x direction C)in the positive y direction D)in the negative y direction E)in the positive x direction between the charges and in the negative x direction elsewhere

Accepted Answer

On the x-axis, the electric field due to the positive charge at the origin will be in the negative x-direction (towards the negative charge). Similarly, the electric field due to the negative charge will be in the positive x-direction (away from the negative charge). Therefore, between the charges, the net electric field will be in the positive x-direction, and outside the charges, the net electric field will be in the negative x-direction. Therefore, the correct choice is E, where the electric field is in the positive x-direction between the charges and in the negative x-direction elsewhere.

Question 19

Positive charge +Q is uniformly distributed on the upper half of a rod and a negative charge -Q is uniformly distributed on the lower half.What is the direction of the electric field at point P, on the perpendicular bisector of the rod? 
A)" $\uparrow$ "
B)" $\downarrow$ "
C)" $\leftarrow$ "
D)" $\rightarrow$ "
E) ""

Accepted Answer

Since the charges are uniformly distributed, the electric field at point P due to the top half of the rod cancels out with the electric field due to the bottom half of the rod along the horizontal direction, leaving only the vertical component of the electric field. By symmetry, the vertical components of the electric field due to the top and bottom halves of the rod are equal in magnitude, but opposite in direction, so they cancel out. Therefore, there is no electric field along the vertical direction (i.e. perpendicular to the rod), and the correct direction of the electric field at point P is downward, which is represented by the arrow pointing downwards () in choice B.

Question 20

Charge is placed on the surface of a 2.7-cm radius isolated conducting sphere.The surface charge density is uniform and has the value 6.9 * 10^-6 C/m².The total charge on the sphere is: A)5.7 *10^-10 C B)1.6*10^-8 C C)3.2 * 10^-8 C D)6.3 *10^-8 C E)7.5 * 10^-⁴ C

Accepted Answer

The total charge on the sphere can be found by multiplying the surface charge density with the surface area of the sphere:

Q = ρA

where Q is the total charge, ρ is the surface charge density, and A is the surface area.

The surface area of a sphere is given by:

A = 4πr^2

where r is the radius of the sphere.

Substituting the given values, we get:

Q = (6.9 x 10^-6 C/m^2) x 4π(0.027 m)^2 = 6.3 x 10^-8 C

Therefore, the answer is D, 6.3 x 10^-8 C.

Quiz 22: Electric Fields

Two point particles, one with charge +8 10^-9 C and the other with charge-2 0 10^-9 C, are separated by 4 m.The electric field midway between them is:

An electric dipole consists of a particle with a charge of +6 * 10^-6 C at the origin and a particle with a charge of -6 * 10^-6 C on the x axis at x = 3 * 10^-3 m.Its dipole moment is:

A charged particle is placed in an electric field that varies with location.No force is exerted on this charge:

Two point particles, with the same charge, are located at two vertices of an equilateral triangle.A third charged particle is placed so the electric field at the third vertex is zero.The third particle must:

A total charge of 6.3 *10^-8 C is distributed uniformly throughout a 2.7-cm radius sphere.The volume charge density is:

An electric dipole consists of two charges, ±2.5 µC, separated by 1.0 x 10^-4 m and centered on the origin.If the dipole is oriented along the x axis, what is the electric field at x = 15 cm?

A disk with a uniform positive surface charge density lies in the x-y plane, centered on the origin.Along the positive z axis, the direction of the electric field is:

A cylinder has a radius of 2.1 cm and a length of 8.8 cm.Total charge 6.1 *10^-7 C is distributed uniformly throughout.The volume charge density is:

Two point charges are arranged as shown.In which region could a third charge +1 C be placed so that the net electrostatic force on it is zero?

A disk with a uniform positive surface charge density lies in the x-y plane, centered on the origin.The disk contains 2.5 x 10^-6 C/m² of charge, and is 7.5 cm in radius.What is the electric field at z = 15 cm?

Comparing the field of a single point charge with the field of an electric dipole,

A spherical shell has an inner radius of 3.7 cm and an outer radius of 4.5 cm.If charge is distributed uniformly throughout the shell with a volume density of 6.1 *10^-4 C/m³ the total charge is:

The electric field due to a uniform distribution of charge on a spherical shell is zero:

Two charged point particles are located at two vertices of an equilateral triangle and the electric field is zero at the third vertex.We conclude:

An electric dipole consists of a particle with a charge of +6 * 10^-6 C at the origin and a particle with a charge of -610^-6 C on the x axis at x = 3 10^-3 m.The direction of the electric field due to the dipole at points on the x axis is:

Charge is placed on the surface of a 2.7-cm radius isolated conducting sphere.The surface charge density is uniform and has the value 6.9 * 10^-6 C/m².The total charge on the sphere is:

Quiz 22: Electric Fields

Positive charge Q is uniformly distributed on a semicircular rod.What is the direction of the electric field at point P, the center of the semicircle?

Two point particles, one with charge +8 *10-9 C and the other with charge-2 *0 10-9 C, are separated by 4 m.The electric field midway between them is:

An electric dipole consists of a particle with a charge of +6 * 10-6 C at the origin and a particle with a charge of -6 * 10-6 C on the x axis at x = 3 * 10-3 m.Its dipole moment is:

A charged particle is placed in an electric field that varies with location.No force is exerted on this charge:

Two point particles, with the same charge, are located at two vertices of an equilateral triangle.A third charged particle is placed so the electric field at the third vertex is zero.The third particle must:

The diagram shows two identical particles, each with positive charge Q.The electric field at point P on the perpendicular bisector of the line joining them is:

A total charge of 6.3 *10-8 C is distributed uniformly throughout a 2.7-cm radius sphere.The volume charge density is:

An electric dipole consists of two charges, ±2.5 µC, separated by 1.0 x 10-4 m and centered on the origin.If the dipole is oriented along the x axis, what is the electric field at x = 15 cm?

A disk with a uniform positive surface charge density lies in the x-y plane, centered on the origin.Along the positive z axis, the direction of the electric field is:

A cylinder has a radius of 2.1 cm and a length of 8.8 cm.Total charge 6.1 *10-7 C is distributed uniformly throughout.The volume charge density is:

Two point charges are arranged as shown.In which region could a third charge +1 C be placed so that the net electrostatic force on it is zero?

A disk with a uniform positive surface charge density lies in the x-y plane, centered on the origin.The disk contains 2.5 x 10-6 C/m2 of charge, and is 7.5 cm in radius.What is the electric field at z = 15 cm?