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

Dielectric, how dielectric mat is used for high voltage safety ? how it wor...

how dielectric mat is used for high voltage safety ? how it works?

How do you compute tensile strength, Q. How do you compute tensile strength...

Q. How do you compute tensile strength? Answer:- Tensile strength is not actually calculated it's measured. It is classified as the point at which a sample of material fai

High frequency alternating current by a loud speaker, Give reason that ultr...

Give reason that ultrasonics not be produced by passing high frequency alternating current by a loud speaker At these high frequencies, inductive reactance is so high where is

Measurement of wavelength of monochromatic light, Q. Measurement of Wavelen...

Q. Measurement of Wavelength of Monochromatic Light? Monochromatic Light is allowed to fall on plate G 1 . The M.I. is adjusted for circular fringes. For this mirror M 1 is ma

Determine the mean voltage over half a cycle, An alternating voltage is tri...

An alternating voltage is triangular in shape, rising at a constant rate to a maximumof 300V in 8ms and then falling to zero at a constant rate in 4ms. The negative half cycle

Define resistance, The characteristics of substance by virtue of which it o...

The characteristics of substance by virtue of which it opposes the flow of current by it, is called as the resistance.

What is the cross-sectional area of a wire, Some wire of cross-sectional ar...

Some wire of cross-sectional area 1mm 2 has a resistance of 20 ?. Determine (a) the resistance of a wire of the same length and material if the cross-sectional area is 4mm 2 ,

Dipole moment, what is the electric field when both the charges are same in...

what is the electric field when both the charges are same in dipole

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