MY CART (5)

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: R

There are no items in this cart.
Continue Shopping

X

“Hurray! You have won the gift voucher. Redeem your points now."

X

                   

microscopic form of ohms law

4 years ago

Share

Answers : (1)

                                        

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

4 years ago

Post Your Answer

More Questions On Electric Current

Ask Experts

Have any Question? Ask Experts

Post Question

 
 
Answer ‘n’ Earn
Attractive Gift
Vouchers
To Win!!!
Click Here for details
please explain me Biot – Savart Law
 
 
Biot and Savart conducted many experiments to determine the factors on which the magnetic field due to current in a small conductor depends. The results of the experiments are summarized as ...
 
noogler one month ago
 
Biot and Savart conducted many experiments to determine the factors on which the magnetic field due to current in a conductor depends. The results of the experiments are summarized as...
 
grenade one month ago
power of a cell
 
 
Power of bulb P = 4.5 V Voltage in bulb = 1.5 V Current in the bulb i will be equla to 2E / 9 2E /9 = P / V E = 9P/2V E = 9*4.5/2*1.5 E = 13.5 V Regards Nirmal Singh Askiitians Faculty
  img
Nirmal Singh. one year ago
The voltage needed for starting the glow of the lamp and the voltage, when the lamp extinguishes, are not equal. Explain why?
 
 
Hi, To get the lamp started you need a spike ofhigh voltageto get the arc started. The colder the lamp is, the higher voltage you need to get a start. The voltage 'forces' current...
  img
Shobhit Varshney 8 months ago
why must bicyclist lran inward while taking turn along unbanked road
 
 
let if the body doesn’t bend inward, If yoy make the free ody diagram, then friction would provide centripetal force. Since friction acts at the contact of cylist with ground, we see there...
 
Abhishek Singh 6 months ago
What is the approximate peak value of alternating current producing four times the heat produced per second by a steady current of 2A in resistor.??? 2.8 A, 4 A, 5.6 A, 8 A
 
 
I rms = 2*I steady (this is given in the question i.e. four times the heat produced) I rms =I max /1.414 Using the above 2 relations we can find out that, I max =2.828 I steady . I max...
  img
Aziz Alam 10 months ago
 
i cant understand your 1 st equation ,,,can you please eloberate it
 
rouf ahmad 6 months ago
View all Questions »