Electric Potential and Electric Field

Oct 13, 2025 by wbrum.org 80 views

Introduction

Electric potential is a measure of the potential difference in electric potential energy per unit charge between two points in an electric field. It is an important concept in physics, particularly in the study of electricity and magnetism. In this article, we will explore the electric potential between two charges and how it changes as the distance between them increases.

Electric Potential and Electric Field

The electric potential at a point in space is defined as the potential difference between that point and a reference point, usually taken to be at infinity. It is measured in volts (V) and is a scalar quantity. The electric field, on the other hand, is a vector quantity that represents the force per unit charge at a point in space. It is measured in newtons per coulomb (N/C).

Electric Potential Energy

The electric potential energy of a charge is the energy it possesses due to its position in an electric field. It is a measure of the work done against the electric field to move a charge from one point to another. The electric potential energy of a charge is given by the equation:

U = qV

where U is the electric potential energy, q is the charge, and V is the electric potential.

Electric Potential and Distance

The electric potential between two charges decreases as the distance between them increases. This is because the electric field strength decreases with distance, and the electric potential is directly proportional to the electric field strength. The electric potential between two charges can be calculated using the equation:

V = k * q1 * q2 / r

where V is the electric potential, k is Coulomb's constant, q1 and q2 are the charges, and r is the distance between them.

Problem

A charge of $$2.55 \times 10^{-4} C$$ is held 0.350 m from a second charge of $$7.62 \times 10^{-6} C$$. The second charge is released. When it reaches a distance of 1.55 m from the first charge, how much has the electric potential increased?

Solution

To solve this problem, we need to calculate the electric potential at the initial and final positions of the second charge.

Initial Position

The initial position of the second charge is 0.350 m from the first charge. We can calculate the electric potential at this position using the equation:

V_initial = k * q1 * q2 / r_initial

where V_initial is the electric potential at the initial position, k is Coulomb's constant, q1 and q2 are the charges, and r_initial is the initial distance between the charges.

V_initial = (8.99 * 10^9 N * m^2 / C^2) * (2.55 * 10^-4 C) * (7.62 * 10^-6 C) / (0.350 m)

V_initial = 1.43 * 10^3 V

Final Position

The final position of the second charge is 1.55 m from the first charge. We can calculate the electric potential at this position using the equation:

V_final = k * q1 * q2 / r_final

where V_final is the electric potential at the final position, k is Coulomb's constant, q1 and q2 are the charges, and r_final is the final distance between the charges.

V_final = (8.99 * 10^9 N * m^2 / C^2) * (2.55 * 10^-4 C) * (7.62 * 10^-6 C) / (1.55 m)

V_final = 4.63 * 10^2 V

Increase in Electric Potential

The increase in electric potential is the difference between the electric potential at the final position and the electric potential at the initial position.

ΔV = V_final - V_initial

ΔV = (4.63 * 10^2 V) - (1.43 * 10^3 V)

ΔV = -8.67 * 10^2 V

The negative sign indicates that the electric potential has decreased as the distance between the charges increased.

Conclusion

In this article, we have explored the electric potential between two charges and how it changes as the distance between them increases. We have calculated the electric potential at the initial and final positions of a second charge and found that the electric potential has decreased as the distance between the charges increased. This is because the electric field strength decreases with distance, and the electric potential is directly proportional to the electric field strength.

References

[1] Halliday, D., Resnick, R., & Walker, J. (2013). Fundamentals of Physics (10th ed.). John Wiley & Sons.
[2] Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers (10th ed.). Cengage Learning.
[3] Tipler, P. A. (2017). Physics for Scientists and Engineers (6th ed.). W.H. Freeman and Company.

Keywords

Electric potential
Electric field
Electric potential energy
Coulomb's constant
Distance
Charge
Electric potential difference

Discussion

The electric potential between two charges is an important concept in physics, particularly in the study of electricity and magnetism. It is a measure of the potential difference in electric potential energy per unit charge between two points in an electric field. The electric potential decreases as the distance between the charges increases, and it is directly proportional to the electric field strength. In this article, we have calculated the electric potential at the initial and final positions of a second charge and found that the electric potential has decreased as the distance between the charges increased. This is because the electric field strength decreases with distance, and the electric potential is directly proportional to the electric field strength.

Introduction

In our previous article, we explored the electric potential between two charges and how it changes as the distance between them increases. We calculated the electric potential at the initial and final positions of a second charge and found that the electric potential has decreased as the distance between the charges increased. In this article, we will answer some frequently asked questions related to the electric potential between two charges.

Q&A

Q1: What is electric potential?

A1: Electric potential is a measure of the potential difference in electric potential energy per unit charge between two points in an electric field. It is an important concept in physics, particularly in the study of electricity and magnetism.

Q2: How does electric potential change with distance?

A2: Electric potential decreases as the distance between the charges increases. This is because the electric field strength decreases with distance, and the electric potential is directly proportional to the electric field strength.

Q3: What is Coulomb's constant?

A3: Coulomb's constant is a fundamental constant in physics that relates the electric force between two charges to the distance between them. It is denoted by the symbol k and has a value of approximately 8.99 x 10^9 N m^2/C2.

Q4: How do you calculate electric potential?

A4: Electric potential can be calculated using the equation:

V = k * q1 * q2 / r

where V is the electric potential, k is Coulomb's constant, q1 and q2 are the charges, and r is the distance between them.

Q5: What is the difference between electric potential and electric field?

A5: Electric potential is a measure of the potential difference in electric potential energy per unit charge between two points in an electric field, while electric field is a measure of the force per unit charge at a point in space. Electric potential is a scalar quantity, while electric field is a vector quantity.

Q6: Can electric potential be negative?

A6: Yes, electric potential can be negative. This occurs when the electric field is directed towards a point in space, and the electric potential at that point is lower than the electric potential at a reference point, usually taken to be at infinity.

Q7: How does electric potential relate to electric potential energy?

A7: Electric potential energy is the energy a charge possesses due to its position in an electric field. Electric potential is a measure of the potential difference in electric potential energy per unit charge between two points in an electric field.

Q8: Can electric potential be used to calculate the work done against an electric field?

A8: Yes, electric potential can be used to calculate the work done against an electric field. The work done against an electric field is equal to the change in electric potential energy, which is given by the equation:

W = q * ΔV

where W is the work done, q is the charge, and ΔV is the change in electric potential.

Q9: How does electric potential relate to the electric field strength?

A9: Electric potential is directly proportional to the electric field strength. This means that as the electric field strength increases, the electric potential also increases.

Q10: Can electric potential be used to calculate the electric field strength?

A10: Yes, electric potential can be used to calculate the electric field strength. The electric field strength can be calculated using the equation:

E = k * q / r^2

where E is the electric field strength, k is Coulomb's constant, q is the charge, and r is the distance between the charges.

Conclusion

In this article, we have answered some frequently asked questions related to the electric potential between two charges. We have discussed the definition of electric potential, how it changes with distance, and how it relates to electric field strength and electric potential energy. We have also provided equations for calculating electric potential and electric field strength.

References

[1] Halliday, D., Resnick, R., & Walker, J. (2013). Fundamentals of Physics (10th ed.). John Wiley & Sons.
[2] Serway, R. A., & Jewett, J. W. (2018). Physics for Scientists and Engineers (10th ed.). Cengage Learning.
[3] Tipler, P. A. (2017). Physics for Scientists and Engineers (6th ed.). W.H. Freeman and Company.

Keywords

Electric potential
Electric field
Electric potential energy
Coulomb's constant
Distance
Charge
Electric potential difference