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

Calculate the pressure and temperature, A box is divided into two parts of ...

A box is divided into two parts of equal volume via a partition. The box is thermally insulated from the surroundings. Consider that compartment 1 contains an ideal gas A at P 0 ,

What is surface tension, It is found that when a liquid is free from the ex...

It is found that when a liquid is free from the external forces, it always gets the shape of a spherical drop. It is due to, for a needed mass, a sphere has the least field area. I

Physical arrangement of resistors, Physical arrangement of resistors: B...

Physical arrangement of resistors: Before we look at some problems it is necessary to warn you that physical appearances can be deceptive. When components are mounted they are

Franklins Bells, (Assume the metallic ball is spherical with a diameter d ...

(Assume the metallic ball is spherical with a diameter d = 2.5 cm. Let''s also assume it is made out of nickel, which has a density of roughly 9 g/cm 3 .) After it first touches

Equation for the equivalent capacitance, Derive mathematical equation for t...

Derive mathematical equation for the equivalent capacitance (Capacity) when capacitors are connected in series.

Doppler Effect, Draw a picture of a moving source and the waves surrounding...

Draw a picture of a moving source and the waves surrounding it according to what you observed in this experiment. How does the spacing of the wave-fronts in front of the source com

Illustrate the newton s laws of motion, Q. Illustrate the Newton s laws of ...

Q. Illustrate the Newton s laws of motion? Answer:- 1. A body at rest will stay at rest and one in motion will remain in motion until and unless acted upon by an external

Calculation of speed of light, how to calculate speed of light?  The sp...

how to calculate speed of light?  The speed of light in vacuum, normally denoted by symbol c, is a universal physical constant which is very important in various areas of physi

What is meant by the statement - charge is quantized, What do you mean by u...

What do you mean by understand by the statement ‘charge is quantized'? The electric lines of force do not intersect. Why?

What is value of amplification factor for valve, A triode valve which is ac...

A triode valve which is acting as an amplifier gives a voltage gain of 30. If anode resistance is 20 K ? for valve and load resistance is 60 K ?, what is value of amplification fac

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