MSE 2090 Chapter 18 Equations Exam Questions and Answers

MSE 2090 Chapter 18 Equations Exam
Questions and Answers
V - ANSWER-- applied voltage
- units: volts [J/C]

I - ANSWER-- current
- time rate of charge passage
- units: amperes [C/s]

R - ANSWER-- resistance of the material through which the current is passing
- units: ohms [V/A]
- value is influenced by specimen configuration
- for many materials, is independent of current

V = IR - ANSWER-- Ohm's Law
- relates current I -- or time rate of charge passage -- to the applied voltage V

ρ - ANSWER-- electrical resistivity
- reciprocal of conductivity
- units: ohm-meters [Ω * m]

l - ANSWER-- distance between two points at which the voltage is measured

A - ANSWER-- cross-sectional area perpendicular to the direction of the current

ρ = RA / l - ANSWER-- Electrical resistivity--dependence on resistance, specimen
cross-sectional area, and distance between measuring points

ρ = VA / Il - ANSWER-- electrical resistivity--dependence on applied voltage, current,
specimen cross-sectional area, and distance between measuring points

σ - ANSWER-- electrical conductivity
- reciprocal of resistivity
- units: reciprocal ohm-meters [ (Ω * m)^-1 ]

σ = 1 / ρ - ANSWER-- reciprocal relationship between electrical conductivity and
resistivity

J - ANSWER-- current density
- current per unit of specimen area I/A

E (written in cursive) - ANSWER-- electric field intensity
- voltage difference between two points divided by the distance separating them