| Definition | Resistance inside a power source (battery, cell) | Inherent resistive property of a material |
| Depends on | Battery/cell construction and internal components | Material type and temperature |
| Role | Causes voltage drop and energy loss inside battery | Determines resistance of wire or resistor of given dimensions |
| Unit | Ohms (Ω) | Ohm-meter (Ω·m) |
| Usage | Important for battery efficiency and performance | Used to calculate resistance of conductors and insulators |
| Example | Dry cell internal resistance ~1-2 Ω | Copper resistivity ≈1.68×10−8Ω⋅m≈1.68×10−8Ω⋅m |
| Nature | Resistance inside a battery or power source | Intrinsic property of a material |
| In circuit | Modeled as small resistor rr in series with emf | Applies to resistors, wires, conductors |
