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Physics Chapter 21: Electric Charge and Fields

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  • What letter represents electric charge?
    Electric charge is represented by the letter \(q\) or \(Q\).
  • What is the SI unit of electric charge?
    The SI unit of electric charge is the coulomb (C).
  • What letter represents the number of particles?
    The number of particles is represented by the letter \(N\) and is unitless.
  • What letter represents the number of moles?
    The number of moles is represented by the letter \(n\) and measured in moles (mol).
  • What letter represents the electric field?
    The electric field is represented by the letter \(E\) and measured in newtons per coulomb (N/C).
  • What letter represents the electric dipole moment?
    The electric dipole moment is represented by the letter \(p\) and measured in coulomb-meters (C⋅m).
  • What is the value and unit of the elementary charge?
    The elementary charge is \(e=1.602\times10^{-19}\) coulombs (C).
  • What is the mass of an electron?
    The mass of an electron is \(m_e=9.11\times10^{-31}\) kilograms (kg).
  • What is the mass of a proton?
    The mass of a proton is \(m_p=1.67\times10^{-27}\) kilograms (kg).
  • What is the electrostatic constant and its unit?
    The electrostatic constant is \(k=8.99\times10^{9}\) and measured in newton meter squared per coulomb squared (N⋅m²/C²).
  • What is the relationship between the electrostatic constant \(k\) and permittivity of free space \(\varepsilon_0\)?
    The relationship is \(k=\frac{1}{4\pi\varepsilon_0}\).
  • Write the equation that shows charge is quantized.
    Charge quantization is expressed as \(Q_{tot}=\pm N e\).
  • Write the equation that shows mass is transferred when charge is transferred.
    Mass transferred is given by \(M_{transferred}=N m_e\).
  • State Coulomb's Law equation.
    Coulomb's Law is \(F_q=k \frac{|q_1 q_2|}{r^2}\).
  • How do like and unlike charges behave toward each other?
    Like charges repel and unlike charges attract.
  • Write the equation relating electrostatic force to electric field.
    The relation is \(F=qE\).
  • How do positive and negative charges behave in an electric field?
    Positive charges experience force in the direction of the field, negative charges experience force opposite to the field direction.
  • Write the equation for the electric field due to a point charge.
    Electric field at distance r is \(E(r)=k \frac{|q|}{r^2}\).
  • Describe the direction of an electric field.
    Electric field points away from positive charges and toward negative charges.
  • Write the equation defining the electric dipole moment.
    Electric dipole moment is defined as \(p=qd\), where q is charge and d is separation distance.
  • How is the direction of the electric dipole moment defined?
    It points from the negative point charge to the positive point charge.