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 area of the surface of water through, A small bulb is placed at...

A small bulb is placed at the bottom of a tank containing water to a depth of 80 cm. What is the area of the surface of water through which light from the bulb can emerge out? Refr

Explain the picture-archiving system, Question 1. Explain the picture-a...

Question 1. Explain the picture-archiving system used in diagnostic imaging departments. 2. Discuss the role of Medical Imaging Informatics in modern radiology departments.

A floater to show surface tension, A floater to show surface tension Be...

A floater to show surface tension Bend a piece of small copper wire into a ring about 8 cm in diameter. Attach two other pieces of wire rigidly to conflicting sides of the ring

Define self inductances and mutual inductances, a. Measure the force among ...

a. Measure the force among two linear, parallel, long conductors carrying currents in opposite direction. b. Measure self inductances and mutual inductances among two co-axial s

Magnetic field lines of a stationary bar magnet, Indicate all that is incor...

Indicate all that is incorrect about the statement The magnetic field lines of a stationary bar magnet move from the north pole of the bar magnet to the south pole of the bar magne

SOUND, WHEN SAME MUSIC IS PLAYED IN VIOLIN AND VEENA WE SHALL HEAR SOUND OF...

WHEN SAME MUSIC IS PLAYED IN VIOLIN AND VEENA WE SHALL HEAR SOUND OF?

Kinematics, the maximum height attained by a projectile and its horizontal...

the maximum height attained by a projectile and its horizontal range are equal to each other if the projectile projected at an angle [theta] given by ?

Characteristic of a photodiode, a) Sketch an IV characteristic of a photodi...

a) Sketch an IV characteristic of a photodiode, showing how the curve shifts as a result of the illumination intensity incident on the device being varied. b) Indicate on the c

Are end fitting standard, Are end fitting standard? No, end fitting are...

Are end fitting standard? No, end fitting are not standard. Each system manufacturer favors a type of termination for his fibers along with threads, pressure glands, rivets or

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