Resistivity, Physics

RESISTIVITY:

Resistance may be defined as that property of a substance which opposes (or restricts) the flow of current (or electrons) through it. The practical as well as MKS (or SI) unit of ohm (O). 1 ohm is defined as that resistance between two points of a conductor which produces a current of one ampere. When a potential difference of 1 volt is applied to it.

If I is the current flowing through a conductor of resistance R across which a potential difference V is applied then according to ohm's law.

                                                                                      I=V/R

Where V is in volts, R is in the ohms and I is in amperes.

Resistance of a material is:

(a)          Directly proportional to its length, l R α l

(b)         Inversely proportional to its area of cross section a, Rα1/a

Combining above two facts me have R α l/a

   Or       R=ρl/A

Where ρ(rho) is a constant depending upon the nature of the material and is known as the specific resistance or resistivity of the material. Putting l=1 and a=1 expression we have R=ρ. Hence resistance of a material of unit length having unit cross-sectional area is defined as the resistivity.

Posted Date: 7/21/2012 7:34:07 AM | Location : United States







Related Discussions:- Resistivity, Assignment Help, Ask Question on Resistivity, Get Answer, Expert's Help, Resistivity Discussions

Write discussion on Resistivity
Your posts are moderated
Related Questions
What is the Specific Heat of Copper? Ans) 387 J/Kg. C or  0.0924 Cal/g.C


A 2.1 kg block slides along a horizontal surface with a coefficient of kinetic friction μ k = 0.31. The block has a speed v = 1.4 m/s when it strikes a massless spring head-on.

Rolling Disc Imagine a rectangular tray lying flat on a horizontal table. Suppose in which the tray has vertical sides, and this a plate (or disc) lies flat on the table and r

Which of the following isn't true of an electric field? Answer An electric field can as well as does exist in vacuum. Except for the one about vacuum the entire the answe

Standing Wave Formation Below given animation depicts two waves moving by a medium in opposite directions. The blue wave is moving to the right and the green wave is moving to

What is an intrinsic semiconductor? How can this material be changed into (i) P-type (ii) N-type extrinsic semiconductor? Describe with the help of energy band diagrams

Define the brightness mode of display in brief. B-Mode Into the B-mode or Brightness mode of display, the time-of-flight (i.e., travel time) of the sound energy is exhibited


Write down the Maxwell's equation in differential form for free space.