All Flashcards
What are the differences between Resistivity (ρ) and Resistance (R)?
Resistivity: Material property (Ω⋅m), independent of dimensions | Resistance: Object property (Ω), depends on material, length, and area.
What are the differences between Ohmic and Non-Ohmic devices?
Ohmic: Follows Ohm's Law (V=IR), linear V-I graph | Non-Ohmic: Does not follow Ohm's Law, non-linear V-I graph.
What are the differences between EMF and Terminal Voltage?
EMF: Total voltage provided by a battery before current flows | Terminal Voltage: Actual voltage available in a circuit when current is flowing, accounting for internal resistance.
Compare and contrast resistors in series and parallel.
Series: Current is the same through all resistors, total resistance increases. | Parallel: Voltage is the same across all resistors, total resistance decreases.
What is the definition of Current Density (J)?
Current per unit area (A/m²). It's a vector related to the electric field (E) by J = E/ρ, where ρ is resistivity.
What is the definition of Resistivity (ρ)?
A material's opposition to the flow of electric current, measured in Ω⋅m.
What is the definition of Resistance (R)?
The overall opposition to current flow in a specific object, measured in Ohms (Ω).
What is the definition of Electromotive Force (EMF or ε)?
The total energy a battery can provide per unit charge, measured in Volts. It's the voltage before any current flows.
What is the definition of Terminal Voltage (Vₜ)?
The actual voltage available in a circuit when current is flowing, which is less than the EMF due to internal resistance.
What is the definition of Internal Resistance (r)?
The resistance within a battery that causes the terminal voltage to be less than the EMF when current flows.
How do you calculate the total resistance of resistors in series?
Add the individual resistances: Rₛ = R₁ + R₂ + R₃ + ...
How do you calculate the total resistance of resistors in parallel?
Use the reciprocal formula: 1/Rₚ = 1/R₁ + 1/R₂ + 1/R₃ + ...
How do you calculate resistance (R) given resistivity (ρ), length (L), and cross-sectional area (A)?
Use the formula: R = ρL/A
How do you calculate electrical power (P) given current (I) and voltage (V)?
Use the formula: P = IV. You can also use P = I²R or P = V²/R if you know current and resistance, or voltage and resistance.
How do you calculate the terminal voltage (Vₜ) of a battery given EMF (ε), current (I), and internal resistance (r)?
Use the formula: ε = V_T + Ir, rearranged to V_T = ε - Ir