Sign In | Subscribe
Start learning today, and be successful in your academic & professional career. Start Today!
Loading video...
This is a quick preview of the lesson. For full access, please Log In or Sign up.
For more information, please see full course syllabus of AP Physics 1 & 2
  • Discussion

  • Download Lecture Slides

  • Table of Contents

  • Transcription

  • Related Books

Bookmark and Share

Start Learning Now

Our free lessons will get you started (Adobe Flash® required).
Get immediate access to our entire library.

Sign up for Educator.com

Membership Overview

  • Unlimited access to our entire library of courses.
  • Search and jump to exactly what you want to learn.
  • *Ask questions and get answers from the community and our teachers!
  • Practice questions with step-by-step solutions.
  • Download lesson files for programming and software training practice.
  • Track your course viewing progress.
  • Download lecture slides for taking notes.
  • Learn at your own pace... anytime, anywhere!

Electric Potential

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Question 1 0:14
  • Question 2 0:42
  • Question 3 1:08
  • Question 4 1:43
  • Question 5 2:22
  • Question 6 2:49
  • Question 7 3:14
  • Question 8 4:02

Transcription: Electric Potential

Hello everyone and welcome back to Educator.com. 0000

In this mini-lesson, we are going to go over the first page of the APlusPhysics worksheet on electric potential and you can find a link to that worksheet down below the video. 0003

With that, let us dive right in. 0011

Number 1 -- If 1 J of work is required to move 1 C of charge between two points in an electric field, the potential difference between the points is...?0015

Well, potential is going to be the energy divided by the charge, so that will be 1 J/1 C or just 1 volt and 1 × 100 -- 100 is 1, so Number 1 is just a fancy way of writing 1 volt -- our correct answer is Number 1. 0023

Number 2 -- The diagram below represents a positively charged particle about to enter the electric field between two oppositely charged parallel plates. 0043

The electric field will deflect the particle -- well let us think about it. 0051

A positive charge is going to be attracted to the negative and repelled by the positive, so it is going to get deflected that way towards the bottom of the page, so the correct answer is Number 4. 0055

Number 3 -- What is the total amount of work required to move a proton through a potential difference of 100 volts? 0068

Well, if potential difference is work divided by charge, then work is just going to be charge times potential difference. 0075

In that case we are going to say work is going to be equal to the charge on a proton, 1.6 × 10 -19 C × 100 volts (potential difference) is just going to be 1.6 × 10-17 J, so the correct answer there must be Number 2. 0083

Number 4 -- The diagram below represents two electrons (E1) and (E2) located between two oppositely charged parallel plates. 0105

Compare the magnitude of the force exerted by the electric field on (E1) to the magnitude of the force exerted by the electric field on (E2).0112

Remember force is going to be charge times electric field strength. 0119

The electric field strength between two parallel plates is constant between those plates as long as you stay away from the edges...so to have an equal electric field, they have the same charge, they must have the same force. 0124

All right, Number 5 -- Which electrical unit is equivalent to 1 J? 0142

Well, to do that a joule is a unit of work, so I am going to use the equation Work = charge × voltage and the units of work (J), must be equal to the units of charge times voltage or coulombs × volts. 0146

So the correct answer is going to be Number 4 -- a coulomb times a volt. 0162

Number 6 -- If 60 J of work is required to move 5 C of charge between two points in an electric field, what is the potential difference between these points? 0170

Well potential difference is work divided by charge, so that will be 60 J/5 C or 12 volts -- Answer Number 2. 0179

Number 7 -- In the diagram below, proton (P), neutron (N), and electron (E) are located as shown between two oppositely charged plates. 0193

The magnitude of the acceleration will be greatest for...? 0203

Well, right away we can eliminate the neutron. 0207

The neutron is not going to have any acceleration because there is not going to be any force on it; it has no charge. 0209

The proton is going to fill a force toward the negative side and the electron is going to fill a force toward a positive side and because they each have the same charge, they will fill the same force, but which will have the greater acceleration?0215

Well, if they have the same force, they have different masses. 0227

The one with the smallest mass is going to have the greatest acceleration and that is going to be the electron, so the correct answer there must be Number 3. 0231

One more here -- An electron is accelerated through a potential difference of 2.5 × 104 volts in the cathode ray tube of a computer monitor. 0242

Calculate the work in joules done on the electron.0259

If V = W/Q, then W (work) = Charge × voltage, so W = 1.6 × 10-19 C (charge on electron) × 2.5 × 104 volts (voltage). 0265

And when I do that I come up with a work done on the electron of about 4 × 10-15 J. 0284

All right, that takes you through page 1 of the worksheet on electric potential. 0295

If you had trouble with it, now would be a great time to go review the lesson on electric potential. 0300

If it went very well, then you are probably ready for the AP level problems. 0305

Thanks so much for your time everyone and make it a great day!0309