PHYSICAL QUANTITY
Electrical resistance: formulas and units of measurement
Electrical resistance: symbol R, unit Ohm. Formulas and explanations for Electricity, Oscillations and waves.
RR\text{Ом}ohm
KEY CONNECTIONS
Formulas
R=\frac{U}{I}R = U / I
R=\rho\frac{l}{S}R = ρl / S
X_L=2\pi\nu LXᴸ = 2πνL
X_C=\frac{1}{2\pi\nu C}Xᶜ = 1 / (2πνC)
R=R_0(1+\alpha t)R = R₀(1 + αt)
NOTATION
Quantities in formulas
- R
- Electrical resistance is a measure of a conductor's resistance to electric current.
- U
- Electric voltage is the work done by the electric field when transferring a unit charge.
- I
- Current strength is the charge passing through the cross section of a conductor per unit time.
- \rho
- Resistivity is a characteristic of a material’s ability to resist current.
- l
- Conductor length is the length of the conductor section under consideration.
- S
- Area is the size of a surface or cross section.
- X_L
- Inductive reactance is the resistance of the coil to alternating current.
- \nu
- Frequency is the number of repetitions of a process per unit of time.
- L
- Inductance is the ability of a conductor to create a magnetic field when current passes.
- X_C
- Capacitance is the resistance of a capacitor to alternating current.
- C
- Electrical capacity is the ability of a conductor or capacitor to accumulate charge.
- R_0
- Initial resistance - resistance at the selected initial temperature.
- \alpha
- Temperature coefficient is a characteristic of the change in resistance when heated.
- t
- Temperature is a measure of the thermal state of the body.
THEORY
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PRACTICE
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DIRECTORY