How do you calculate the total resistance of resistors in series?
Add the individual resistances: Rโ = Rโ + Rโ + Rโ + ...
How do you calculate the total resistance of resistors in parallel?
Use the reciprocal formula: 1/Rโ = 1/Rโ + 1/Rโ + 1/Rโ + ...
How do you calculate resistance (R) given resistivity (ฯ), length (L), and cross-sectional area (A)?
Use the formula: R = ฯL/A
How do you calculate electrical power (P) given current (I) and voltage (V)?
Use the formula: P = IV. You can also use P = IยฒR or P = Vยฒ/R if you know current and resistance, or voltage and resistance.
How do you calculate the terminal voltage (Vโ) of a battery given EMF (ฮต), current (I), and internal resistance (r)?
Use the formula: ฮต = V_T + Ir, rearranged to V_T = ฮต - Ir
What are the differences between Resistivity (ฯ) and Resistance (R)?
Resistivity: Material property (ฮฉโ
m), independent of dimensions | Resistance: Object property (ฮฉ), 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 happens when the length of a wire increases?
The resistance of the wire increases proportionally.
What happens when the cross-sectional area of a wire increases?
The resistance of the wire decreases proportionally.
What happens when a real battery has internal resistance?
The terminal voltage is less than the EMF when current is flowing.
What happens when resistors are added in series?
The total resistance of the circuit increases.
What happens when resistors are added in parallel?
The total resistance of the circuit decreases.
