Skip to main content

My Channels

24. Electric Force & Field; Gauss' Law

Coulomb's Law (Electric Force)

24. Electric Force & Field; Gauss' Law

Coulomb's Law (Electric Force)

Guided videos.

Learn with Patrick

Go to the course

Charges In A Line (Find Zero Force)

Charges In A Line (Find Zero Force)

Charges In A Triangle (Rank Force Pairs)

Charges In A Triangle (Rank Force Pairs)

Charges in a Plane

Charges in a Plane

Exploiting Symmetry

Exploiting Symmetry

Electroscope (Find Charge)

Electroscope (Find Charge)

Showing 6 of 6 videos

Practice this topic

Multiple Choice

If the force between two charges is F when the distance is d, what will the force between the two charges be if they were moved to a distance of 2d?

Has a video solution.

Multiple Choice

In which direction will the −1 C charge move? If it has a mass of 10 g, what will its initial acceleration be?

Has a video solution.

Multiple Choice

What is the direction of the net force on the charge at the center of the square in the following figure?

Has a video solution.

Multiple Choice

What is the distance between a

10 μ C

24 μ C

charge if the magnitude of the force between them is

1.2 mN

Multiple Choice

- 4.00 nC

charge at the origin. A

9.00 nC

charge is on the x-axis at

x = 2.00 m

5.00 nC

charge is on the y-axis at

y = - 1.00 m

. What is the total force on the

- 4.00 nC

charge at the origin? Give your answer as a magnitude and an angle counterclockwise from the positive x-axis.

Multiple Choice

What is the relationship between the gravitational force between two electrons,

F_{G}

. and the electric force between two electrons,

F_{E}

Multiple Choice

3.0 nC

charge is at the origin, a

- 12 nC

x = 2.0 cm

. Where, on the x-axis, could you place a

- 45 nC

charge so that it would experience no net force?

Textbook Question

Three point charges are arranged along the x-axis. Charge q1 = +3.00 mC is at the origin, and charge q2 = -5.00 mC is at x = 0.200 m. Charge q3 = -8.00 mC. Where is q3 located if the net force on q1 is 7.00 N in the -x-direction?

Has a video solution.

Textbook Question

Three point charges are arranged on a line. Charge q3 = +5.00 nC and is at the origin. Charge q2 = -3.00 nC and is at x = +4.00 cm. Charge q1 is at x = +2.00 cm. What is q1 (magnitude and sign) if the net force on q3 is zero?

Has a video solution.

Textbook Question

Just How Strong Is the Electric Force? Suppose you had two small boxes, each containing 1.0 g of protons. (a) If one were placed on the moon by an astronaut and the other were left on the earth, and if they were connected by a very light (and very long!) string, what would be the tension in the string? Express your answer in newtons and in pounds. Do you need to take into account the gravitational forces of the earth and moon on the protons? Why? (b) What gravitational force would each box of protons exert on the other box?

Textbook Question

Two small plastic spheres are given positive electric charges. When they are 15.0 cm apart, the repulsive force between them has magnitude 0.220 N. What is the charge on each sphere (b) if one sphere has four times the charge of the other?

Has a video solution.

Textbook Question

Two small plastic spheres are given positive electric charges. When they are 15.0 cm apart, the repulsive force between them has magnitude 0.220 N. What is the charge on each sphere (a) if the two charges are equal and

Has a video solution.

Textbook Question

Two small spheres spaced 20.0 cm apart have equal charge. How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 3.33 * 10^-21 N?

Has a video solution.

Textbook Question

Two small aluminum spheres, each having mass 0.0250 kg, are separated by 80.0 cm. (c) What fraction of all the electrons in each sphere does this represent?

Has a video solution.

Textbook Question

Two small aluminum spheres, each having mass 0.0250 kg, are separated by 80.0 cm. (b) How many electrons would have to be removed from one sphere and added to the other to cause an attractive force between the spheres of magnitude 1.00 * 10^4 N (roughly 1 ton)? Assume that the spheres may be treated as point charges.

Has a video solution.

Textbook Question

Two small plastic spheres each have a mass of 2.0 g and a charge of −50.0 nC. They are placed 2.0 cm apart (center to center). a. What is the magnitude of the electric force on each sphere?

Has a video solution.

Textbook Question

A 2.0 g plastic bead charged to −4.0 nC and a 4.0 g glass bead charged to +8.0 nC are 2.0 cm apart and free to move. What are the accelerations of (a) the plastic bead and

Has a video solution.

Textbook Question

A massless spring is attached to a support at one end and has a 2.0 μC charge glued to the other end. A −4.0 μC charge is slowly brought near. The spring has stretched 1.2 cm when the charges are 2.6 cm apart. What is the spring constant of the spring?

Has a video solution.

Textbook Question

Objects A and B are both positively charged. Both have a mass of 100 g, but A has twice the charge of B. When A and B are placed 10 cm apart, B experiences an electric force of 0.45 N. a. What is the charge on A?

Has a video solution.

Textbook Question

What is the force F on the 1.0 nC charge at the bottom in FIGURE P22.47? Give your answer in component form.

Has a video solution.

Textbook Question

A +2.0 nC charge is at the origin and a −4.0 nC charge is at x=1.0 cm. b. Would the net force be zero for an electron placed at the same position? Explain.

Has a video solution.

Textbook Question

In a simple model of the hydrogen atom, the electron moves in a circular orbit of radius 0.053 nm around a stationary proton. How many revolutions per second does the electron make?

Has a video solution.

Textbook Question

You have a lightweight spring whose unstretched length is 4.0 cm. First, you attach one end of the spring to the ceiling and hang a 1.0 g mass from it. This stretches the spring to a length of 5.0 cm. You then attach two small plastic beads to the opposite ends of the spring, lay the spring on a frictionless table, and give each plastic bead the same charge. This stretches the spring to a length of 4.5 cm. What is the magnitude of the charge (in nC) on each bead?

Has a video solution.

Textbook Question

A 5.0 g ball charged to 1.5 μC is tied to a 25-cm-long string. It swings at 250 rpm in a horizontal circle around a stationary ball charged to −2.5 μC. What is the tension in the string?

Has a video solution.

Textbook Question

Space explorers discover an 8.7×10^17 kg asteroid that happens to have a positive charge of 4400 C. They would like to place their 3.3×10^5 kg spaceship in orbit around the asteroid. Interestingly, the solar wind has given their spaceship a charge of −1.2 C. What speed must their spaceship have to achieve a 7500-km-diameter circular orbit?

Has a video solution.

Textbook Question

What is the force F on the 8.0 nC charge in FIGURE P22.44? Give your answer as a magnitude and an angle measured cw or ccw (specify which) from the +x-axis.

Has a video solution.

Textbook Question

FIGURE P22.52 shows three charges and the net force on charge −q. Charge Q is some multiple α of q. What is α?

Has a video solution.

Textbook Question

You have two small, 2.0 g balls that have been given equal but opposite charges, but you don't know the magnitude of the charge. To find out, you place the balls distance apart on a slippery horizontal surface, release them, and use a motion detector to measure the initial acceleration of one of the balls toward the other. After repeating this for several different separation distances, your data are as follows: Use an appropriate graph of the data to determine the magnitude of the charge.

Has a video solution.

Textbook Question

The identical small spheres shown in FIGURE P22.64 are charged to +100 nC and −100 nC. They hang as shown in a 100,000 N/C electric field. What is the mass of each sphere?

Has a video solution.

Textbook Question

What is the magnitude of the net force on charge A in FIGURE EX22.17?

Has a video solution.

Textbook Question

What is the force F on the 1.0 nC charge in FIGURE EX22.20? Give your answer as a magnitude and a direction.

Has a video solution.

Textbook Question

Two 1.0 g spheres are charged equally and placed 2.0 cm apart. When released, they begin to accelerate at 150 m/s^2. What is the magnitude of the charge on each sphere?

Has a video solution.

Textbook Question

A 3.00-cm-long spring has a small plastic bead glued to each end. Charging each bead to −25 nC expands the spring by 0.50 cm. What is the value of the spring constant?

Has a video solution.

Textbook Question

A small glass bead charged to +6.0 nC is in the plane that bisects a thin, uniformly charged, 10-cm-long glass rod and is 4.0 cm from the rod's center. The bead is repelled from the rod with a force of 840 μN . What is the total charge on the rod?

Has a video solution.

Textbook Question

INT The surface charge density on an infinite charged plane is −2.0×10^−6 C/m^2 . A proton is shot straight away from the plane at 2.0×10^6 m/s . How far does the proton travel before reaching its turning point?

Has a video solution.

Textbook Question

INT In a classical model of the hydrogen atom, the electron orbits the proton in a circular orbit of radius 0.053 nm. What is the orbital frequency in rev/s? The proton is so much more massive than the electron that you can assume the proton is at rest.

Has a video solution.

Textbook Question

An electret is similar to a magnet, but rather than being permanently magnetized, it has a permanent electric dipole moment. Suppose a small electret with electric dipole moment 1.0×10^−7 C m is 25 cm from a small ball charged to +25 nC , with the ball on the axis of the electric dipole. What is the magnitude of the electric force on the ball?

Has a video solution.

Textbook Question

Consider an oil droplet of mass m and charge q. We want to determine the charge on the droplet in a Millikan-type experiment. We will do this in several steps. Assume, for simplicity, that the charge is positive and that the electric field between the plates points upward. (c) A spherical object of radius r moving slowly through the air is known to experience a retarding force Fₔᵣₐ₉ = −6πηr v where η is the viscosity of the air. Use this and your answer to part b to show that a spherical droplet of density ρ falling with a terminal velocity vₜₑᵣₘ has a radius . r = √9ηvₜₑᵣₘ / 2pg

Has a video solution.

Showing 38 of 38 practice