Resistivity, Physics

Assignment Help:

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.


Related Discussions:- Resistivity

Concept of derivative of the function, KINEMATICS II 1. The concept of ...

KINEMATICS II 1. The concept of the derivative of the function is exceptionally important. The derivative shows that how fast the function changes when its argument is changed.

Conductive and convective resistance - surface of the sphere, Show that the...

Show that the Nusselt number for a sphere in a quiescent fluid is 2. Hint: Write the thermal resistance for the outer surface of the sphere in terms as both conductive and conve

Types of bond: metallic bond, METALLIC BOND:   When positive metalli...

METALLIC BOND:   When positive metallic ions are surrounded by a sea of negative electrons, the solid being held together by electrostatic forces then it is called metallic

What is the average acceleration of the door, A 15.2-kg police battering ra...

A 15.2-kg police battering ram exerts an average force of 125 N on a 10.0-kg door. a. What is the average acceleration of the door? b. What is the average acceleration of th

Situation of the converging lens - principle ray 1, Q. Situation of the con...

Q. Situation of the converging lens - Principle Ray 1? Principle Ray I . The easy one just as in the case of the converging lens this ray goes straight through the centre of t

Determine the potential energy of the object, An object with a mass of 5 ki...

An object with a mass of 5 kilograms is a distance of 5 meters above the surface of the earth.  If the acceleration because of gravity is 10 meters per second squared, the pote

Copernican principle , Copernican principle (N. Copernicus) The idea, ...

Copernican principle (N. Copernicus) The idea, recommended by Copernicus, that the Sun, not the Earth, is at the middle of the Universe. Now we know that neither idea is accur

Constraint relation : wedge and block, A block goes on a wedge which in tu...

A block goes on a wedge which in turns goes on a horizontal table, as given in figure. The wedge angle is Φ. As long as the wedge is in met with table, we have the trivial const

Thermonuclear reactions, Thermonuclear reactions: The fusion reactions ...

Thermonuclear reactions: The fusion reactions which require extremely high temperatures are called thermonuclear reactions. The most important thermonuclear reactions take plac

What are intrinsic and extrinsic semiconductors, What are intrinsic and ext...

What are intrinsic and extrinsic semiconductors? A semiconductor is a material that has an electrical conductivity among that of a conductor and an insulator. In a semiconducto

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd