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

What is the proper formula used to calculate acceleration, What is the prop...

What is the proper formula used to calculate acceleration? There are a few. The most famous is a = F/m, where F is the net force applied to a mass, m. Acceleration is also the

What is the weight of the sled and rider, A sled and its rider are perched ...

A sled and its rider are perched at the top o a hill that is 35 m tall. If the gravitational potential energy is 3.0 x 10 4 J. What is the weight of the sled and rider?

Calculate its efficiency as a percentage, A 100 hp car engine operates ata ...

A 100 hp car engine operates ata bout 15 percent efficiency. Assume the engine's water temperature of 85°C is it scold-temperature (exhaust) reservoir and 500°C is its thermal "int

How x-rays are produced, Question 1. How X-rays are produced? Describe ...

Question 1. How X-rays are produced? Describe the properties of X-Rays? 2. Describe the half wave & full wave Rectifications employed in an X-ray tube? 3. Discuss the med

Hard ferromagnetic substances, Hard Ferromagnetic Substances: Those sub...

Hard Ferromagnetic Substances: Those substances that do not lose their magnetism or removing from magnetic field are known as hard magnetic substance such as steel.

Determine the force acting through the bolts of the flange, This spray head...

This spray head discharges water (density 62.4 lbm/ft ) at a rate of 4 ft /s. Assuming irrotational flow and an efflux speed of 65 ft/s in the free jet, determine what force acting

Explain squirrel cage induction motors, Mines Flame proof squirrel cage...

Mines Flame proof squirrel cage induction motors are used in coal mine.

Thermal properties of dielectric materials:, One of the functions of the in...

One of the functions of the insulation is hest transfer. Consider an underground cable under operation. This cable is recommended for operations. This cable is recommended for oper

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