Electrical resistance of the conductor, specific resistance

Electrical resistance of the conductor, specific resistance

The physical quantity that characterizes the ability of a conductor to resist current is called the electrical resistance. It is denoted by the letter R.

The formula for determining the resistance of a conductor

• The physical quantity that indicates the resistance of a given conductor to the current flowing through it is called the resistance of the conductor. R=ρl/A

• The resistance of the conductor is directly proportional to the length l

  
  

• The cross-sectional area A of the resistance of the conductor is inversely proportional

  
  

• The resistivity of the conductor ρ is directly proportional

  
  

The value that characterizes the material of the conductor is called the resistivity. We denote it by ρ. $R=\frac{\rho l}{A}\ \ \ \rightarrow\ \ \ \rho=\frac{RA}{l}$  
Measuring instrument "Ohmmeter".The unit of resistance in the SI system

 $\rho=\frac{RA}{l}=\frac{Ohm\cdot m^2}{m}=Ohm\cdot m$