- It is denoted by the symbol ‘R’.
- It is measured in a unit called ohm (Ω) with the help of a Wheatstone bridge
- The electrical resistance is:
- Directly proportional to its length, l
- Inversely proportional to its area of cross section, A.
- In the equation the constant of proportionality denoted by called rho is called resistivity.
- It is measured in units called ohm metre.
- When length = 1m.
Cross sectional area = 1m2
- Then resistivitybecomes the resistance.
1 Ω m = 100 Ω cm
1 Ω cm = 0.01 Ω m