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 current in the capacitor, A 25nF capacitor is connected in pa...

A 25nF capacitor is connected in parallel with a coil of resistance 2kΩ and inductance 0.20H across a 100V, 4 kHz supply. Determine (a) The current in the coil, (b) The cur

Final image is formed at the near point of the eye, A compound microscope w...

A compound microscope with an objective of 1.0 cm focal length and an eye-piece of 2.0 cm focal length has a tube length of 20 cm. Measure the magnifying power of the microscope, i

What do you mean by leptons, Q. What are leptons? Give examples. Lep...

Q. What are leptons? Give examples. Leptons: Leptons are lighter particles having mass equal to or less than about 207 times the mass of an electron except neutrino an

Explain synchronous condensers, Synchronous Condensers: A synchronous moto...

Synchronous Condensers: A synchronous motor takes a leading current when over-excited and thus behaves as a capacitor. An over-excited synchronous motor running on no load is call

Force mc falling time mars, Surface gravity on Mars is roughly 1/3 that of ...

Surface gravity on Mars is roughly 1/3 that of the Earth. Consider you drop a rock initially at rest from a height Hm on Mars and it takes a time tg to hit the ground. From what he

Explain time of flight, TIME OF FLIGHT: "It is the total time for which...

TIME OF FLIGHT: "It is the total time for which the projectile remains in air". As, the body goes up and comes back to similar level, so it does not cover vertical distance,

Anekardhi shabdh, list of anekardhi shabdh with examples

list of anekardhi shabdh with examples

Electricity, describe the applications of potentiometers

describe the applications of potentiometers

What is magnetic field?, It is the area or region around the material where...

It is the area or region around the material where magnetic properties can be found is called as “magnetic field”.

Lawson criterion, Lawson criterion (J.D. Lawson): A situation for the ...

Lawson criterion (J.D. Lawson): A situation for the release of energy from a thermonuclear reactor. Usually it is stated as the minimum value for the product of the density of

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