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 work done and entropy, One mole of H 2 at 300 K takes a volume o...

One mole of H 2 at 300 K takes a volume of 10 lits in a cylinder fitted with a piston. It is expanded isothermally to 20 lits. Consider ideal behavior for the gas, determine W, Q,

Determine the grating element, A diffraction grating used at normal inciden...

A diffraction grating used at normal incidence provides a spectral line of certain order with wavelength 6000A 0 superimpose on another spectral line of wave length 5000A 0 of th

Explain the law of machines, Q. Explain the Law of Machines? Answer:- ...

Q. Explain the Law of Machines? Answer:- Machines which are utilized to lift a load are governed by the Law of machines which states that the effort to be applied on the m

Explain joule''s law, Explain Joule's Law: "Work done is directly propo...

Explain Joule's Law: "Work done is directly proportional to the heat produced.

What is the principle of generating ultrasonic waves, What is the principle...

What is the principle of generating ultrasonic waves? The general principle comprised in generating ultrasonic waves is to reasons some dense material to vibrate very quickly.

Stationary on inclined plane, A metal rod of mass 10 g and length 10 cm is ...

A metal rod of mass 10 g and length 10 cm is placed on a smooth 60 degree incline. A uniform magnetic field B is applied in the region vertically downwards . If a current of 3 A is

Vector, two forces at right angle with each other have a resultant of 58kN,...

two forces at right angle with each other have a resultant of 58kN, If one of the forces is 40kN find the magnitude of the other forces

Heaviest particle, Heaviest particle is: (1)Meson (2)Neutron  (3)...

Heaviest particle is: (1)Meson (2)Neutron  (3)Proton (4)Electron Ans: 2b)Neutron

Kohlrauschs law, Kohlrausch's law (F. Kohlrausch): If a salt is dissol...

Kohlrausch's law (F. Kohlrausch): If a salt is dissolved into water, the conductivity of the solution is the total of two values one based on the positive ions & the other dep

The frequency of the sound , A source producing sound at frequency 400 Hz i...

A source producing sound at frequency 400 Hz is moving along the Y axis with a speed of 22 metre per second. A listener is situated at position (660m,0). Find the frequency of the

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