History of Electrostatics Quiz

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.