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

Defects of vision and their correction, Defects of vision and their correct...

Defects of vision and their correction There is a simple relationship between the focal length F ,the object distance P and the image distance Q of a thin lens fig(1).

Define in detail about the test of good bricks, Define in detail about the...

Define in detail about the test and characteristics of good bricks. Tests for bricks 1. Absorption a brick is taken and it is weighed dry. It is then immersed in water for

Electrostatic force and gravitational force, compare the electrostatic forc...

compare the electrostatic force between two protons to the gravitational force acting on them?

Motion, a car of mass 800kg is pulling a trailer 300kg where sin a=1|200.Re...

a car of mass 800kg is pulling a trailer 300kg where sin a=1|200.Resistance to motion(apart from gravity) is 1.5N per kg of mad for each vehicle.calculate the pulls of the engine a

2-point source interference patterns, 2-Point Source Interference Patterns ...

2-Point Source Interference Patterns The diagram below displays various two-point source interference patterns. The crests of each wave are denoted through a thick line althoug

What is electron holography, What is Electron Holography? Electron holo...

What is Electron Holography? Electron holography is an application of holography procedures to electron waves quite than light waves. Electron holography was invented through D

Explain the wave particle duality, Explain the Wave Particle Duality An...

Explain the Wave Particle Duality Any object in the world can be considered to be a particle or wave and will exhibit properties of both. For example, a photon of light, an ele

Ionization energy and potential, The energy needed to ionize an atom is kno...

The energy needed to ionize an atom is known as ionization energy. It is the energy needed to make the electron jump from the present orbit to the infinite orbit.

Evaluate the frequency of the lowest note, The overall length of a particul...

The overall length of a particular wind instrument is 35.0 cm. The resonating air column vibrates as ina pipe that is open at both ends. (a) Find the frequency of the lowest not

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