Electric Potential question

In summary, an electron is released from rest 4m from an infinite plane of positive charge and collides with the plane. The electric field produced by the plane has a constant magnitude of 100 V/m. To find the speed of the electron at the point of collision, the force on the electron can be calculated using the equation electric field * charge = force on charge. This force can then be used in the kinematics equation V_f^2 = V_i^2 + 2ad to solve for the final velocity of the electron.
  • #1
jcpwn2004
49
0

Homework Statement



An electron is released from rest 4m from an infinite plane of positive charge. The plane produces an electric field with a constant magnitude of 100 V/m. How fast is the electron moving when it collides with the plane? Mass of E = 9.11x10^-31kg.

Homework Equations



Not sure... Ui + Ki = Uf + Kf?

The Attempt at a Solution

 
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  • #2
You are given the electric field, not the voltage at the point so you can't use conservation of energy. Remember, electric field * charge = force on charge. You can use this to find the force on the electron, and then use one of the kinematics equations so solve for the speed.
 
  • #3
kkrizka said:
You are given the electric field, not the voltage at the point so you can't use conservation of energy. Remember, electric field * charge = force on charge. You can use this to find the force on the electron, and then use one of the kinematics equations so solve for the speed.

Ok so I did F=EfxQ...(100 v/m)(1.6x10-19) = 1.6x10^-13 J. And then F=ma so A = (1.6x10^-17)/(9.11x10-31) = 1.756x10^13 m/s...

I'm lost what to do after that...what kinematic equation should i use?
 
  • #4
The one that involves initial, final velocities, acceleration and displacement. I believe it is
[tex]V_f^2 = V_i^2 + 2ad[/tex]
 

1. What is electric potential?

Electric potential is the amount of electrical potential energy per unit charge at a certain point in an electric field.

2. How is electric potential different from electric potential energy?

Electric potential is a property of a point in an electric field, while electric potential energy is a measure of the potential energy that a particle with a certain charge would have at that point.

3. What is the unit of electric potential?

The unit of electric potential is volts (V).

4. How is electric potential calculated?

Electric potential can be calculated by dividing the electric potential energy by the charge at a certain point in an electric field. It can also be calculated by multiplying the electric field strength by the distance between two points.

5. What is the relationship between electric potential and electric potential energy?

Electric potential and electric potential energy have a direct relationship. As the electric potential increases, the electric potential energy also increases. This means that a particle with a higher charge will have a greater electric potential energy at a certain point in an electric field compared to a particle with a lower charge.

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