Question 1 A uniform electric field of magnitude points in the positive x-direction. (a) Find the change in electric potential between the origin and the point (0, 2.1m). (b) Find the change in electric potential between the origin and the point (2.1m, 0). (c) Find the change in electric potential between the origin and the […]

## Physics 115: Lecture 10

Example A set of points in space that are all at the same potential creates / defines an “Equipotential line” Example Note That V = change of potental (“potential difference”) V (better notation?) and, similarly, = displacment vector Which becomes V = -E Solving for Example A) […]

## Problem 21.63

A proton follows the path shown in (Figure 1). Its initial speed is v0 = 2.9×10^6 m/s. Part A What is the proton’s speed as it passes through point P? Express your answer to two significant figures and include the appropriate units.

## Problem 21.40

Part A To what potential should you charge a 3.0 μF capacitor to store 4.0 J of energy?

## Quiz: Electric Forces and Fields

Question 1 Two point charges of equal magnitude are 2.6cm apart. At the midpoint of the line connecting them, their combined electric field has a magnitude of 114NC. Find the magnitudes of the two charges. (NOTE: Enter your answer in picocoulombs, pC.) Question 2 Four point charges, each of magnitude are located at the corners […]

## Physics 115: Lecture 09

Yalda’s Notes: My Notes: Example Calculate the work done in the moving this test charge the distance r Coulomb’s Law (for point charge) Potential Energy Example 2 So, here, Q’s potential energy changed by “Electric Potential” Then we can write Example (Capacitor) Calculate the […]

## Quiz: The Electric Force

Question 1 Two identical negative charges are located on the y-axis, at y = +4m and y = -4m. A positive charge of 0.25C is placed on the x-axis at x = 2m. What direction does the net force on the proton point? Select one: A. Along the -x-axis B. At a 45 degree angle […]

## Physics 115: Lecture 08

Charge Density Line Charge density ( ) z = distance from the wire. of an “infinite” wire Example C is deposited onto a 75cm long wire. Calculate at 3cm from the wire. L = 0.75m z = 3cm = Concept of a surface charge density Example […]

## Problem 20.32

Storm clouds may build up large negative charges near their bottom edges. The earth is a good conductor, so the charge on the cloud attracts an equal and opposite charge on the earth under the cloud. The electric field strength near the earth depends on the shape of the earth’s surface, as we can explain […]

## Problem 20.25

Part A What is the strength of the electric field at the position indicated by the dot in (Figure 1)? Express your answer using two significant figures. Part B What is the direction of the electric field at the position indicated by the dot in the figure? Specify the direction as an angle above the […]