Calculating Force and Kinetic Energy in an Electric Field

In summary, the conversation is discussing the concept of electric field and its application in a specific problem involving an electron projected between two oppositely charged metal plates. The force on the electron is calculated and the question of how much its kinetic energy increases due to the electric field is raised. The equations used to solve the problem are also mentioned. One person suggests considering the work done by the electric force and another points out the use of the accelerating (electric) potential difference.
  • #1
adrianx
5
0
electric field

I can't find any straight forward solutions to this problem.. it's not addressed in the textbook (even though there is a chapter problem about it) and the internet doesn't have what I need either. I'm hoping someone could give me some insight on this.

An electron (q = -1.602 x 10^-19 C) is projected horizontally into the space between two oppositely charged metal plates. The electric field between the plates is 503.0 N/C, directed up.
(a) While in the field, what is the force on the electron?

(b) If the vertical deflection of the electron as it leaves the plates is 3.20 mm, how much has its kinetic energy increased due to the electric field?

For (a), I found the force to be 8.058E-17N down.

(b), I think I need to know what the velocity is. I know a few equations but I don't know how to use them for this.
The equations I know are:
K = (1/2)mv^2 which I found (on the 'net) to be equal to eV = (1/2)mv^2.
kinematic equations
F = ma = qE
 
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  • #2
Fot the second point,how about considering that the work done by the electric force is equal to the variation of the KE?

Daniel.

P.S.What "V" are u talking about?
 
  • #3
Genius! The chapter and my professor didn't mention anything about work (or kinetic energy as it applies to the electric field for that matter).

Thank you so much :)

I don't know what that V is.. some webpages I found just used it. When I tried to apply it, I just used the elementary charge e (don't ask me why..)
 
  • #4
That probably is the ACCELERATING (ELECTRIC) POTENTIAL DIFFERENCE.In this problem,it's unknown and moreover useless...

Daniel.
 

FAQ: Calculating Force and Kinetic Energy in an Electric Field

What is an electric field?

An electric field is a region in space where an electrically charged particle experiences a force. It is created by the presence of electric charges and is represented by lines of force that point in the direction of the force.

How does an electric field affect a TV tube?

An electric field is used in a TV tube to accelerate and deflect electrons, which create the images we see on the screen. The electric field is created by charged plates inside the tube that attract or repel the electrons, controlling their movement and ultimately producing the picture on the screen.

What is the role of the electric field in color TV?

In color TV, the electric field is used to accelerate and deflect three different types of electrons: red, green, and blue. Each type of electron is attracted to a specific color phosphor on the inside of the TV screen, creating the full range of colors that we see on the screen.

How is the strength of the electric field in a TV tube controlled?

The strength of the electric field in a TV tube is controlled by adjusting the voltage applied to the charged plates inside the tube. A higher voltage will create a stronger electric field, resulting in more acceleration and deflection of the electrons. This ultimately affects the brightness and clarity of the images on the screen.

Can the electric field in a TV tube be dangerous?

The electric field in a TV tube is generally not dangerous to humans, as the voltage used is relatively low. However, it is important to exercise caution when handling the inside of a TV tube, as there may be residual voltage present even after the TV is unplugged. It is always best to let a trained professional handle any repairs or maintenance on a TV tube.

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