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 maximum velocity of rocket, A popular toy on the market some ...

A popular toy on the market some years ago was the water rocket. Water (at 10°C) was loaded into a plastic rocket and pressurized with a hand pump. The rocket was released and woul

Searle''s apparatus, why metallic frame used in searles apparatus

why metallic frame used in searles apparatus

Estimate ground level no concentration, A stack emitting 85 g/s of NO has a...

A stack emitting 85 g/s of NO has an effective stack height of 100 m. The wind speed is 3 m/s at 10 m, and it is a cloudy summer day.  Estimate ground level NO concentration:

What happens if or electrical joint is loose, What occurs if electrical con...

What occurs if electrical connection or electrical joint is loose? Ans: Because of loose connection at joints resistance at that point will increase thereby the I²R loses ar

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

What are non ohmic and ohmic devices, What are non ohmic and ohmic devices?...

What are non ohmic and ohmic devices? Give examples The manganin wire is used in the manufacturing of standard resistances. Why?

Magnetic effects of current, a)  Explain the magnetic effects of current? ...

a)  Explain the magnetic effects of current? b)  Do the diagram to show the direction of motion of the conductor:

PULLEY, In a pulley system the eqn for length of inextensible string is y p...

In a pulley system the eqn for length of inextensible string is y plus sq. root of x^2+h^2=constant ? how to differentiate y plus sq. root of x^2+h^2=constant to get vel & accn rel

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