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

Explain about the intermodal dispersion in optical fibers, Explain about th...

Explain about the intermodal dispersion in optical fibers. Intermodal Dispersion Δτ im ) This dispersion arises even when light that is launched into the fiber is s

What is extrinsic semiconductor, (i) It is also known as impure semiconduct...

(i) It is also known as impure semiconductor. (ii) The phenomena of adding impurity is known as Doping.

Circuit theorems, The superposition theorem is a very useful network theore...

The superposition theorem is a very useful network theorem. Write its statement

What average force does the bullet exert on the gun, A 7.25-g bullet is fir...

A 7.25-g bullet is fired from a gun. The muzzle velocity of the bullet is 223 m/s. Suppose that the bullet accelerates at a constant rate along the barrel of the gun before it

What is the velocity of the combined system - collision, A 10 kilogram body...

A 10 kilogram body initially moving with a velocity of 10 meters per second makes a head-on collision with a 15 kilogram body initially at rest.  The two objects stick together

What is polymorphism, What is Polymorphism Polymorphism in materials sc...

What is Polymorphism Polymorphism in materials science is the skill of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be fou

What is a neutron, What is a neutron? A neutron is a subatomic particle...

What is a neutron? A neutron is a subatomic particle. Neutron is one of the building blocks of the atom. It has a mass of about 1.675 x 10-27 kg. Its spin is + 1/2 and that

Define isothermal process, Define isothermal process For isothermal pr...

Define isothermal process For isothermal process temperature remains constant i.e.  Δu = 0.  Thus according to first law of thermodynamics ΔQ =Δw Heat supplied to the syste

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