Thank you for registering.

One of our academic counsellors will contact you within 1 working day.

Please check your email for login details.
MY CART (5)

Use Coupon: CART20 and get 20% off on all online Study Material

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping

microscopic form of ohms law

microscopic form of ohms law

Grade:

1 Answers

Ashwin Sinha
520 Points
9 years ago

Dear Harpreet Singh,

Ohm's Law is the linear proportionality between current and voltage that occurs for most conductors of electricity. A graph of voltage against current is a straight line. The gradient is the resistance.

The most well known form of Ohm's law is V=IR, where V is the voltage, I is the current and R is the resistance. However there is another form of Ohm's law which often used by physicists that operates on a microscopic level, relating the current density J to the conductivity σ and the electric field, E.

To see how consider, the volume of material with faces of area A a distance l apart. With an e.m.f. V across the faces of the material

  • the current is proportional to the voltage V
  • the current is proportional to the surface area A
  • and the current is inversely proportional to the distance l.

The current is therefore,

I = VAσ/l.

R = l/Aσ

The proportionality constant σ is the conductivity of the material.

V/l = |E|, and J = I/A in the direction of E so in general we have the constitutive relation.

J = σE

 

                      Good Luck!!!!!!

 

 Plz. approve my answer, if you loved it, by clicking 'Yes' given below!!!!!!Plz. Plz. Plz.!!!!!!! Don't forget!!!!!!!!Smile

Think You Can Provide A Better Answer ?

Provide a better Answer & Earn Cool Goodies See our forum point policy

ASK QUESTION

Get your questions answered by the expert for free