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

Distinguish between the terms average value and rms value, A convex lens of...

A convex lens of refractive index 1.5 has a focal length of 18 cm in air. Measure the change in its focal length when it is immersed in water of refractive index. Distinguish am

Produce a schematic diagram of the system, Produce a schematic diagram of t...

Produce a schematic diagram of the system: The steam that leaves the super-heater is expanded from 130bar at 535°C to 25.2bar at 310°C in a high pressure turbine. The steam fr

Determine total bond dissociation energy of the reactants, Given that dH fo...

Given that dH for the reaction is -92.2 kJ mol-1, which is larger, the total bond dissociation energy of the reactants or the total bond dissociation energy of the products?

Lyman series, Lyman series: The series which define the emission spect...

Lyman series: The series which define the emission spectrum of hydrogen while electrons are jumping to the ground state. All lines are in the ultraviolet.

Making a jam jar aquarium, Making a jam jar aquarium If a large glass t...

Making a jam jar aquarium If a large glass tank is not available, practically any glass vessel can be used as a easy aquarium if it is well stocked with submerged water plants

How newton''s ring can be obtained in the laboratory, Q.   Explain how Newt...

Q.   Explain how Newton's ring can be obtained in the laboratory. Why Newton's rings are circular in shape? How the Newton's rings are used to find refractive index of liquid?

Maximum and minimum magnitude of the resultant, The maximum and minimum mag...

The maximum and minimum magnitude of the resultant of two forces are 16 N and 4N.Measure t he magnitude of individual force. Let the two vector be a and b then maxim resultant

2d representation of the diamond unit cell, 2D representation of the diamon...

2D representation of the diamond unit cell In a 2D projection of the diamond unit cell, the base plane of the unit cell ABCD is shown by a square and the atoms in the base pla

Explain fistulas, Explain Fistulas Fistulas  :  an abnormal opening ...

Explain Fistulas Fistulas  :  an abnormal opening among an internal cavity and another cavity or the surface. Haemodialysis  :  removal of chemical waste from the blood

Dispersion of light, Dispersion of Light: When a beam of light is permi...

Dispersion of Light: When a beam of light is permitted to pass by a prism, it splits in a band of different colors. This band of different colors is known as spectrum and the p

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