History of Electrostatics Quiz

10 Questions

Which of the following materials allow electric charges to move freely?

Copper, aluminum, and silver

What is the main characteristic of insulators?

Charging by rubbing creates charge in a small area

Which materials exhibit characteristics between insulators and conductors?

Silicon and germanium

What is the process of charging by conduction?

Moving electrons from a charged object to another object

What happens when a conductor is charged in a small region?

The charge readily distributes itself over the entire surface of the material

In the complex plane shown in Fig. 1, if Z = Z1+Z2, what is the value of Z?

-2+j4

In the equation (2Z-3𝒁), what is the solution set of Z if the equation equals -5-j5?

-5-j5

Using Z = Z2+𝒁 a, what is the value of Z if Z1 = j1 2?

-2+j4

What is the polar form (r∠θ) of the vector shown in Fig. 2?

5∠-53.1

What is the length of vector ⃗⃗⃗⃗⃗ 𝐶A − ⃗⃗⃗⃗⃗ BA if it equals 53.1 +x -3i?

3+3√2

Study Notes

A Bit of History

Ancient Greeks observed electric and magnetic phenomena as early as 700 BC.
They found that amber, when rubbed, became electrified and attracted pieces of straw or feathers.
Magnetic forces were discovered by observing magnetite attracting iron.

William Gilbert and Charles Coulomb

William Gilbert (1600) found that electrification was not limited to amber.
Charles Coulomb (1785) confirmed the inverse square relationship of electrical forces.

Properties of Charge

Nature's basic carrier of negative charge is the electron.
An object becomes charged by gaining or losing electrons.
Electric charge is always conserved, meaning it is not created or destroyed, only exchanged between objects.
Charge is quantized, meaning all charge is a multiple of a fundamental unit of charge, symbolized by e.
Quarks are the exception to this rule.
Electrons have a charge of –e, while protons have a charge of +e.
The SI unit of charge is the Coulomb (C), where e = 1.6 × 10^(-19) C.

Equations and Solutions

The solution of the equation (𝒙 − 𝟑)𝟐 = −𝟔𝒙 + 𝟏𝟖 has one root.
The solution of the equation [(𝒙 − 𝟐)𝟐 − 𝟑𝒙 − 𝟔 = −𝟏𝟐] is (-2, 5).
The two roots (5, -5) can construct an equation 𝑥² − 10𝑥 + 25 = 0.
The roots of the equation (2𝑥² + 20𝑥 = −42) are (-7,-3).
Using the "completing the square" method to solve the equation ( 𝑎𝑥² + 12𝑥 + 2 = −8) leads to (𝑥 + 3)² = 4 where a= 2.
For the complex numbers A=8+j6, B=a+j3, the value of a is 4 if |A|=2|B|.
The magnitude of |C| is 4 if C= 𝐵 .
The angle of the polar form of C is θc = 36.8 if C=A/B.
The magnitude of Z is |Z|= 10 if z = 6+𝑗8 −3−𝑗4.
The simplest form of the number Z = 3𝑗² +5𝑗³ −10𝑗⁵ +5(𝑗² +𝑗³ +𝑗⁴)² is Z = -2+j15.