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

Second, Second; s: The basic SI unit of time, explained as the period ...

Second; s: The basic SI unit of time, explained as the period of time equal to the duration of 9 192 631 770 periods of the radiation equivalent to the transition among two hy

Disadvantages of low power factor, Disadvantages of Low Power factor G...

Disadvantages of Low Power factor Greater conductor size : To transfer or distribute a fixed amount of power at constant voltage, the conductor will have to carry more current

Optics, determination of suger concentration in water by refractive index

determination of suger concentration in water by refractive index

Explain centripetal force, Explain Centripetal force?? Sir Isaac Newton...

Explain Centripetal force?? Sir Isaac Newton suggested that motion in a straight line is most natural, and that deviations from this type of motion are caused by a force pullin

What is fission and fusion, What is Fission and Fusion? Fission: The ...

What is Fission and Fusion? Fission: The breaking down of a Nucleus (not atom) into minute nuclei. It is usually induced by a neutron. For instance, a Helium nucleus (known a

What is otto cycle, What is Otto Cycle? The cycle of a highly idealized...

What is Otto Cycle? The cycle of a highly idealized gasoline engine can be approximated by the Otto cycle. 1 → 2 and 3 → 4 are adiabatic compression and expansion, respectively

Define some factors which cause a system to oscillate, Write down the facto...

Write down the factors which force a system to oscillate?

Kinematics., a ball is thrown horizontally from a point 100 m above the gro...

a ball is thrown horizontally from a point 100 m above the ground with a speed of 20 m/sec .find the time it takes to reach the ground...

Calculate the final mass of water, 2 Kg of ice at -20 degree C is mixed wit...

2 Kg of ice at -20 degree C is mixed with 5Kg of water 20 degree C in an insulating vessel having negligible heat capacity. Calculate the final mass of water remaining in the comta

Illustrate the term semiconductor laser, Illustrate the term semiconductor ...

Illustrate the term semiconductor laser. Semiconductor Laser (Laser diode): It is a laser wherein semiconductors (characteristically direct band-gap semiconductors) can be u

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