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RESISTANCE AND CONDUCTANCE

Resistance:

  • The property of a material which opposes the flow of current is known Resistance.
  • The Units of Resistance is
  1.  kilo ohm's.
  2. Mega ohm's.
  3. Milli ohm's.
  4. Micro ohm's. 
  • The device used for this purpose is known as a Resistor.
  • These are widely used in electric circuits.

Law of Resistance:

  • Resistance is directly proportional to length of the material.
  • Resistance is inversely proportional to area of the conductor
         R=(rho)×(l/a)
 Here,
         rho-Resistivity or specific resistance
         l-length of material
         a-Area of the material.
  • The unit of this Resistivity are
  1. Ohm's per meter
  2. Ohm's per meter cube
  3. Ohm's per centimetre
  4. Ohm's per centimetre cube
 Where,
          1 ohm per meter=100 ohm's per centimetre

Conductance:

  • It is just a reciprocal of Resistance.
  • It is the property of a material which allows the flow of current.
  • One of the best conducting material is copper.
  • The units of this condutance is Mho.
  • It id denoted by a letter G
                G=(conductivity)×(a/l)
  • The units of this conductivity are mho per meter.



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