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

How many significant digits in 100m, How many significant digits are there ...

How many significant digits are there in each of the following measurements? a. 100 m 1 b. 0.0023 m/s 2 c. 100.1 m 4 d. 2.0023 5

Determine the power factor on no-load, A transformer takes a current of 1A...

A transformer takes a current of 1A when its primary is connected to a 300V, 50Hz supply, the secondary being on open-circuit. If the power absorbed is 120watts, Determine

PHYSICAL CHEMISTRY, Calculate the density of sodium metal. The length of th...

Calculate the density of sodium metal. The length of the body-centered cubic unit cell is 4.24 A.

Hydrazine monopropellant, What is the mass of a two stage launch vehicle ca...

What is the mass of a two stage launch vehicle capable of putting a 100kg satellite into orbit around Mars, beginning in a parking orbit altitude at Earth of 200 km. Solve this pro

Find the electric flux density, Two parallel plates having a p.d. of 250V b...

Two parallel plates having a p.d. of 250V between them are spaced 1mm apart. Determine the electric field strength. Find also the electric flux density when the dielectric a

Determine the brewsters angle for a glass slab, Determine the Brewster's an...

Determine the Brewster's angle for a glass slab (µ=1.5) immersed in water (µ=4/3).

Magnetic effect of the earth, Magnetic effect of the earth is? Magnetic...

Magnetic effect of the earth is? Magnetic effect of the earth. The earth behaves as it has got a big magnet, running as mot a big magnet, running almost from its north to South

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