Work Done By the Electric Field

In summary, the work required to bring a 3 C point charge from infinity to point X, where the change in electric potential is -6 V, is -18 J. This is the work done by an external force to overcome the force of the electric field.
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Homework Statement


How much work is required to bring a 3 C point charge from infinity to a point X. The change in electric potential from infinity to point X is -6 V.


Homework Equations


-QV=W



The Attempt at a Solution


The answer is -18 J. MY confusion is whether this is the work done by the electric field or an external force? My guess is it is the work done by an external force, however my book says different? Or maybe I'm misinterpreting the question can you confirm that it's an external force?
 
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Assuming the charge starts and ends its journey at rest, it is the work you have to do to overcome the force of the electric field in bringing that charge to X.
 

1. What is work done by the electric field?

The work done by the electric field is the amount of energy transferred to a charged particle as it moves through the electric field. It is measured in joules (J).

2. How is work done by the electric field calculated?

The work done by the electric field is calculated by multiplying the magnitude of the electric field (E) by the distance (d) the charged particle has moved in the direction of the field. Mathematically, it is expressed as W = qEd, where q is the charge of the particle.

3. What is the relationship between work done by the electric field and potential energy?

The work done by the electric field is equal to the change in potential energy (PE) of the charged particle. This means that when work is done on a charged particle, its potential energy increases and vice versa.

4. Can the work done by the electric field be negative?

Yes, the work done by the electric field can be negative if the direction of the electric field and the direction of movement of the charged particle are opposite. This indicates that the electric field is doing work on the particle, decreasing its potential energy.

5. How does the work done by the electric field affect the motion of charged particles?

The work done by the electric field can either speed up or slow down the motion of charged particles, depending on the direction of the electric field and the charge of the particle. A positive charge will accelerate in the direction of the electric field, while a negative charge will decelerate. This is due to the conservation of energy principle, where the work done by the electric field is converted into kinetic energy of the particle.

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