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

What is angular velocity, The power of change of angular displacement with ...

The power of change of angular displacement with respect to time is known as angular velocity.

How to demagnetize the screwdriver, Q. Jingdan turned a screwdriver into a ...

Q. Jingdan turned a screwdriver into a magnet by rubbing it with a strong bar magnet to pick up a screw that has fallen into an inaccessible spot. How could he demagnetize his

Electrostatics, in a uniform electric field, the potential is 10v at the or...

in a uniform electric field, the potential is 10v at the origin and 8v at each of the points (1,0,0),(0,1,0) and (0,0,1).Find the potential at the point (1,1,1).

Angular Acceleration of Earth, 2. The earth’s rotation about its axis chang...

2. The earth’s rotation about its axis changes measurably over time; see http://en.wikipedia.org/wiki/Leap_second and http://en.wikipedia.org/wiki/Tidal_acceleration for detai

First law of black hole dynamics, Black-hole dynamic laws; laws of black-ho...

Black-hole dynamic laws; laws of black-hole dynamics first law of black hole dynamics For interactions among black holes & normal matter, the conservation laws of mass-

Dielectric strength, Electrical Properties of Dielectric Materials The ...

Electrical Properties of Dielectric Materials The term "Dielectric strength" of a dielectric material means the maximum electric field strength that it can withstand intrinsica

Strains are measured by strain gage elements, A rectangular rosette is moun...

A rectangular rosette is mounted on a test structure as shown, loads are applied, and the following strains are measured by strain gage elements 1, 2, and 3: ε 1 = 1500 μm/ m ε

Electric charges, Two charges eachof q=+2 micro coloumb are placed at the v...

Two charges eachof q=+2 micro coloumb are placed at the vertices Q and R of the triangle .the sum of sides PQ and PR is 12cm and their product is 32 cm_2 .the potential at point P

What do you mean by alloy, Q. Explain an alloy? Answer:- An alloy ...

Q. Explain an alloy? Answer:- An alloy is a homogeneous hybrid of two or else more elements at least one of which is a metal and where the resulting material has metallic

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