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

Determine the force acting through the bolts of the flange, This spray head...

This spray head discharges water (density 62.4 lbm/ft ) at a rate of 4 ft /s. Assuming irrotational flow and an efflux speed of 65 ft/s in the free jet, determine what force acting

Aameter, aameter - construction and working

aameter - construction and working

Beer lambert''s low, what is meant by positive deviation of beer lambert''s...

what is meant by positive deviation of beer lambert''s low

Explain the meaning of ram effect?, A ram-air intake is any intake design w...

A ram-air intake is any intake design which uses the dynamic air pressure produced by vehicle motion to increase the static air pressure inside of the intake manifold on an engine,

Explain friction of rough surfaces, Friction of rough surfaces Place tw...

Friction of rough surfaces Place two pieces of sandpaper together. Notice the friction that is formed when one is rubbed against the other. Now put some grease among the pieces

Determine properties of monochromatic wave, A plane monochromatic wave trav...

A plane monochromatic wave travelling in a homogeneous medium goes into a denser medium. What are the changes in (i) Frequency (ii) amplitude (iii) speed of propagation & (iv) Phas

ball is dropped in a hole passing through centre of earth, what will happe...

what will happen when a ball is dropped in a hole passing through the centre of earth through out diametrically?

Instantaneous speed and velocity, Instantaneous velocity and speed are expl...

Instantaneous velocity and speed are explained at a given or particular instant and are shown by  ,

Show the mathematical relation connecting n, Show the mathematical relation...

Show the mathematical relation connecting n,u,v and R for refraction at a spherical surface concave towards a point object in a denser medium producing a virtual image.

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