Electric Forces and Electric Fields. Objective: Define and apply Coulomb’s Law to calculate the electric force between charged particles. Plot electric field lines and calculate electric fields for simple charge distributions. Bellwork – please write the answer on your homework.
Define and apply Coulomb’s Law to calculate the electric force between charged particles.
Plot electric field lines and calculate electric fields for simple charge distributions.
k=8.988x109 Nm2/C2 .
Three point charges are placed along the x-axis. A +5 µC charge is located at the origin, a +2 µC charge is located 30 cm to its right, and a -4 µC is located at 50 cm.
Calculate the magnitude and direction of the force exerted on the +2 µc charge by the +5 µC charge.
Calculate the magnitude and direction of the force exerted on the +2 µc charge by the -4 µC charge
What is the magnitude and direction of the net force on the +2 µC charge?
3. Fe = 2.1 N to the right
This process of isolating each set of forces and then adding together their results is called the superposition principle
net F = 0.3 N + 1.8 N
net F = 2.1 N to the right
Examine the following diagram which shows four charges that have been placed on the corners of a square 50 cm on each edge. Determine the net force on the 2 µC charge.
(Nm2/C2)(C)(1/m2) = N/C
oppositely-charged particles like-charged particles
Left is +, right is - both are +
In a 4.00 g of helium, the nuclei are separated from the electrons by a distance of 1 km. What is the magnitude of the electric force between the protons and the electrons?
Calculate the magnitude and direction of the electric field at the origin due to these charges
q1 = -1.00 μC = -1.00 x 10-6 C
q2 = +2.00 μC = +2.00 x 10-6 C
q3 = -1.50 μC = -1.50 x 10-6C
r1 = 3.50 m
r2 = 5.00 m
r3 = 4.00 m
Electric Field Due to Parallel Plates: when two parallel plates are connected across a battery, the plates become charged and an electric field is established between them.
Learn more about pions and other fundamental particles at http://particleadventure.org/
Electric fields are strongest at locations along the surface where the object is most curved
Place four evenly-spaced negative charges along each line.
For each surface show the electric field lines
(a) Surrounding a single positive point charge,
(b) surrounding a single negative point charge
(c) surrounding a larger negative point charge.
(d) Four different surfaces surrounding various parts of an electric dipole.
The Potential Energy (Work) to move charges through an electrical field depends on:
1) Electric charge - a property of the object experiencing the electrical field
2) Distance from source - the location within the electric field
A piece of plastic has a net charge of + 2.00 nC. How many more protons than electrons does this piece of plastic have? What mass was lost by the plastic when it became charged?
Two 1.2-gram balloons are suspended from light strings attached to the ceiling at the same point. The net charge on the balloons is -540 nC. The balloons are distanced 68.2 cm apart when at equilibrium. Determine the amount of tension on the string.
Several electric field line patterns are shown in the diagrams below. Which of these patterns are incorrect? Explain what is wrong with all incorrect diagrams.
An electron in Tammie’s TV is accelerated toward the screen across a potential difference of 22000 V. How much kinetic energy does the electron lose when it strikes the screen?