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

Electrostatic, Why we are showing work done over a closed path is zero to ...

Why we are showing work done over a closed path is zero to prove that electrostatic forces are conservative

what percentage should the pressure of a given mass, By what percentage sh...

By what percentage should the pressure of a given mass of gas be increased,so as to decrease its volume  by 10% at a constant temperature.

Explain velocity-time graph, VELOCITY- TIME GRAPH: The graphs which rep...

VELOCITY- TIME GRAPH: The graphs which represents the variation of velocity of an object with respect to time is known as velocity- time graph.

Direction south to north, An alpa particle is directed vertically upward wi...

An alpa particle is directed vertically upward with a speed of 3 X 104 Km/Sec in a region where a magnetic field of magnitude 1 Tesla exists in the direction south to north. Determ

Angle between plane of polarization and plane of vibration, What is the ang...

What is the angle between plane of polarization and plane of vibration?

Draw the x-y intensity pattern, Consider the 4-f system below where an obje...

Consider the 4-f system below where an object is placed at the input plane and is illuminated by a plane wave  With the object from part a) inserted in the input plane, a m

Ideal gas laws, Ideal gas laws Boyle's law At constant temperat...

Ideal gas laws Boyle's law At constant temperature, the pressure of an ideal gas is inversely proportional to the volume of the gas Charles' law At constant

Motion in one dimension, South African frogs are capable of jumping as far ...

South African frogs are capable of jumping as far as 10.0m in one hop. Suppose one of these frogs makes exactly 15 of these jumps in a time interval of 60.0s. What is the frogs ave

What is an illuminator, What is an illuminator? An illuminator, light g...

What is an illuminator? An illuminator, light generator or source is a box along with a lamp inside, pointing in the direction of an opening where fiber optics is secured. Obvi

Explain the term work function of a metal, Explain the term 'work function'...

Explain the term 'work function' of a metal. The threshold frequency of a metal is f 0 . When the light of frequency 2f 0 is incident on the metal plate, the maximum velocity of e

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