Electrostatics Quiz: Observation & Charges

Course Overview

• The course is graded based on 40% Midterm Exam and Assignments, 20% Practical Exam and Assignments, and 40% Final Paper Exam.
• The course covers topics including Electricity, Magnetism, and Electric Circuits.

Electricity

• Electric charge and substances, Electric Force, Column`s Law, Current (AC and DC), Electric Flux, Gauss Law, Electric Volt, Capacitance, and dielectrics.
• Properties of electric charges:
• Electric forces and charges can be demonstrated through simple experiments.
• There are two kinds of electric charges: positive and negative.
• Like charges repel each other, and unlike charges attract each other.
• Coulomb's Law:
• The electric force between two stationary charged particles is inversely proportional to the square of the separation between the particles.
• The electric force is proportional to the product of the charges on the two particles.
• The electric force is attractive if the charges are of opposite sign and repulsive if the charges have the same sign.
• Electric force equation: F = (Ke * q1 * q2) / r^2, where F is the force, Ke is the Coulomb's constant, q1 and q2 are the charges, and r is the distance between the charges.
• Permittivity constant of free space: εo = 8.85 x 10^-12 C^2/N.m^2

Charge and Matter

• Particle symbol:
• Proton (P): positive charge
• Neutron (N): neutral
• Electron (E): negative charge
• Charge and mass of particles:
• Proton: 1.6 x 10^-19 C, 1.67 x 10^-27 Kg
• Neutron: 0, 1.67 x 10^-27 Kg
• Electron: -1.6 x 10^-19 C, 9.1 x 10^-31 Kg

Examples and Applications

• Example 1: The attractive force between a comb and bits of paper demonstrates the existence of electric forces and charges.
• Example 2: The magnitudes of the electric force and the gravitational force between the electron and proton in a hydrogen atom can be calculated using Coulomb's law.
• Example 3: The electric force between two objects with charges of 2 μC and 6 μC can be calculated using Coulomb's law.
• Example 4: The value of two equal charges that repel each other with a force of 0.1 N when situated 50 cm apart in a vacuum can be calculated using Coulomb's law.
• Example 5: The electric force and gravitational force between two 40-gram masses each with a charge of 3 μC placed 50 cm apart can be compared.
• Example 6: The net force on an object with a charge of -4 μC can be calculated using Coulomb's law and vector addition.