Motion of Charged Particles in Electric Fields

In summary, the question is asking to calculate the displacement of an electron that is initially at rest and is accelerated through a potential difference of 350 V and then enters deflecting plates of 50 V. The velocity of the electron is found to be 1.1 x 10^7 m/s and the problem can be solved using techniques similar to projectile motion in a uniform gravitational field. This involves finding the electric force and acceleration, and using SUVAT equations to calculate the displacement.
  • #1
CARL0001

Homework Statement


This is the question: An electron at rest of mass 9.11 × 10−31 kg is accelerated through a potential difference of 350 V. It then enters some deflecting plates of 50 V with dimensions as shown. Calculate the distance x (deflection of the electron) (Charge on an electron is 1.6 × 10−19 C)

Given Diagram: https://gyazo.com/73ada230623b2ba00a80f5be8001fade

Homework Equations


W = Fd = ½mv2 = qΔV , Δt = Δd / v

https://gyazo.com/0b2211e627a646ec5437e72c0848e6d9

The Attempt at a Solution


So the question is asking to find the displacement in the y direction which is x on the diagram. i first found the original velocity between the vertical plates. in order to get the original velocity i used the following equation qΔV= ½mv2. i rearranged the formula and solved for v which i got to be 1.1 x 10^7 m/s. from my understanding this is the initial velocity of the electron when it enters the horizontal plates. I'm confused where to go from here. i can't find any practice examples similar to this type of question. I'm confused whether or not you need to split this section into vertical and horizontal components. i think next i have to find the electric force and then use that to find the acceleration. then i think you can use
Δt = Δd / v to find the time between the plates. after this i think you can find the displacement using one of the 5 kinematic equations. however I'm confused since i don't know if you need to split this up into different components.
 
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  • #2
Have you covered projectile (parabolic motion) in uniform gravitational fields? If so you can use similar techniques to solve your problem.
HINT In one direction the electron continues moving with constant velocity and perpendicular to that it moves with constant acceleration.
 
  • #3
Dadface said:
Have you covered projectile (parabolic motion) in uniform gravitational fields? If so you can use similar techniques to solve your problem.
HINT In one direction the electron continues moving with constant velocity and perpendicular to that it moves with constant acceleration.
No I'm not familiar with this method, however is my method correct?
 
  • #4
CARL0001 said:
Δt = Δd / v
No, that is only valid for constant velocity. Here you have constant acceleration in the direction of the field. That makes it just like projectiles in near-Earth gravity.
Look up SUVAT.
 

1. How do electric fields affect the motion of charged particles?

Electric fields exert a force on charged particles, causing them to move in the direction of the field if they are positive and in the opposite direction if they are negative. This force is known as the electrostatic force and is proportional to the magnitude of the electric field and the charge of the particle.

2. What is the equation for calculating the force on a charged particle in an electric field?

The force (F) on a charged particle in an electric field is given by the equation F = qE, where q is the charge of the particle and E is the electric field strength. This equation also takes into account the direction of the force, which is in the direction of the electric field for positive charges and opposite to the direction of the electric field for negative charges.

3. How does the velocity of a charged particle change in an electric field?

The velocity of a charged particle in an electric field can change in two ways: the particle can either speed up or slow down depending on the direction of the electric field and the charge of the particle. If the force and velocity are in the same direction, the particle will speed up, while if they are in opposite directions, the particle will slow down.

4. What is the relationship between the electric field and the acceleration of a charged particle?

The acceleration (a) of a charged particle in an electric field is directly proportional to the electric field strength (E) and inversely proportional to the mass of the particle (m). This relationship is described by the equation a = qE/m. This means that a larger electric field will result in a greater acceleration of the particle, while a larger mass will result in a smaller acceleration.

5. How can the motion of a charged particle in an electric field be manipulated?

The motion of a charged particle in an electric field can be manipulated by changing the strength or direction of the electric field. This can be achieved by adjusting the distance between the charged particle and the source of the electric field or by changing the voltage applied to the electric field. Additionally, the motion of the charged particle can be altered by changing the charge or mass of the particle itself.

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