# Electricity and magnetism point charges problem

• ravsau
In summary: I DOING THIS RIGHT?In summary, four equal point charges, three positive and one negative, are fixed in place on a straight line with equal distance d between them. The question asks to calculate the ratio of the largest to the smallest net electrostatic force acting on each charge. No numbers are given, but we can assign +q to the first three charges and -q to the fourth. Using Coulomb's law, we can calculate the force of B on A and then add the forces of C on A and D on A vectorily. We can also calculate the forces on B, C, and D.
ravsau

## Homework Statement

Four point charges have equal magnitudes. three are positive and one is negative, as the diagram shows. they are fixed in place on the same straight line, and adjacent charges are equally separated by a distance d. consider the net electrostatic force acting on each charge. calculate the ratio of the largest to the smallest net force.

(+) ------- d --------- (+) ------- d --------- (+) -------- d --------- (-)

A B C D

## The Attempt at a Solution

This questions has no numbers so I am confused

ravsau said:

## Homework Statement

Four point charges have equal magnitudes. three are positive and one is negative, as the diagram shows. they are fixed in place on the same straight line, and adjacent charges are equally separated by a distance d. consider the net electrostatic force acting on each charge. calculate the ratio of the largest to the smallest net force.

(+) ------- d --------- (+) ------- d --------- (+) -------- d --------- (-)

A B C D

## The Attempt at a Solution

This questions has no numbers so I am confused
You don't need numbers. Let the first three charges be +q and the fourth -q. What is the force of B on A? (hint: Coulomb's law).

Once you work that out, calculate the forces of C on A and of D on A and add them all up vectorily. Then work out the forces on B, C and D.

AM

## 1. What is the difference between electricity and magnetism?

Electricity and magnetism are two separate but closely related phenomena. Electricity is the flow of electric charge, while magnetism is the force exerted by moving electric charges. In other words, electricity is the cause of magnetism, and magnetism is the effect of electricity.

## 2. What is a point charge in electricity and magnetism?

A point charge is an idealized model of an electric charge that is concentrated at a single point in space. It is used to simplify calculations and understand the behavior of electric charges in an electric or magnetic field. In reality, all charges have a finite size and volume, but the point charge model is a useful approximation in many cases.

## 3. How do point charges interact with each other?

Point charges interact with each other through the electric force, which can be attractive or repulsive depending on the charges' signs. If two charges have the same sign, they will repel each other, while opposite charges will attract. The magnitude of the force is determined by Coulomb's law, which states that the force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.

## 4. How is a magnetic field created by a point charge?

When a point charge moves, it creates a magnetic field around it. This is because moving charges produce a current, and a current flowing through a wire creates a magnetic field. The strength and direction of the magnetic field depend on the charge's velocity, with stronger fields created by faster-moving charges.

## 5. How do I solve problems involving point charges in electricity and magnetism?

To solve problems involving point charges, you will need to use the principles of electromagnetism, such as Coulomb's law, Gauss's law, and Ampere's law. You will also need to have a good understanding of vector calculus and be able to apply it to electric and magnetic fields. It is essential to carefully analyze the problem and use the appropriate equations and techniques to solve it correctly.

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