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

Find entropy change in the mixing process, 1.5 kg of Oxygen (N 2 ) and 0.15...

1.5 kg of Oxygen (N 2 ) and 0.15 kg of Helium (He 2 ) are separated by a partition in a vessel.  The Nitrogen is at 5 bar and 90 o C and the Helium at 1 bar and 20 o C.  The part

How long does it take for the water to reach boiling point, How long does i...

How long does it take for the water to reach the boiling point? An iron boiler of mass 230 kg contains 830 kg of water at 18C. A heater supplies energy at the rate of 52,000 kj/

Explain inertia, Inertia: the resistance an object has to a alter in its s...

Inertia: the resistance an object has to a alter in its state of motion. Newton's first law of motion declares that force is NOT required to keep an object in motion. Slide

Determine the speed of electromagnetic wave, A medium is characterised by r...

A medium is characterised by relative permittivity ε r =45 and relative permeability μ r =5. Determine the speed of e-m wave in the refractive and medium index of the medium.

Illustrate huygens principle, State and illustrate Huygens' principle. Expl...

State and illustrate Huygens' principle. Explain the consequences of total internal reflection.

Shape memory alloys, SHAPE MEMORY ALLOYS: A group of metallic materials ...

SHAPE MEMORY ALLOYS: A group of metallic materials that can return to some previously defined shape or size when subjected to the appropriate thermal producer. That is to say, s

Explain first law of newton, Explain Newton's First Law In 1665, at the...

Explain Newton's First Law In 1665, at the age of 23, Newton developed his famous Laws of Motion. They are commonly known as Newton's first, second and third law. Aside from th

Friction and Bouyancy, what is the ratio of the frictional force and the no...

what is the ratio of the frictional force and the normal force ?

Radial acceleration..., So I have a question here and I am totally lost: A ...

So I have a question here and I am totally lost: A car starts from rest and accelerates at a constant rate of 1.1 m/s2. If the radius of the car wheels is 29.0 cm, and the final an

Determine the mutual inductance of the coil, The current in a coil changes ...

The current in a coil changes of 5A to 10A in 10 -2 s. Then an emf of 50 mill volts is induced in a coil neat it. Determine the mutual inductance of the coil.

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