## UnkleRhaukus 2 years ago Is electric current a scalar? Can it be negative?

1. .Sam.

THAT is what I thought also

2. UnkleRhaukus

i got it wrong, i dont really understand why

3. .Sam.

Aw

4. DLS

Current is scalar and it cannot be negative.

5. DLS

$\LARGE I= - \frac{dQ}{dt}$ indicates that flow of current per unit time is decreasing maybe the question posted is a subpart of another question or perhaps incomplete.

6. DLS

@yrelhan4 ? :O

7. yrelhan4

the convention that we follow is movement of -ve charge as current right?

8. raane

@DLS current can be negative

normally we don't take current as a vector and instead use the length vector instead.

10. raane

because its scalar

11. ganeshie8

|dw:1367418867689:dw|

12. ganeshie8

if i assume that way is +ve, then the reverse of it will be -ve. in a circuit we assume current directions initially. based on that we get -ve or +ve numbers after analysis

13. Ruchi.

becoz current does'nt follow vector algebra so, it is scalar.

14. agent0smith

"the convention that we follow is movement of -ve charge as current right?" I think this is why. Current is created by flow of electrons which go from - to +, but current is defined as + to -.

15. agent0smith

Still, this site uses no negative sign, it has your answer... http://physics.tutorvista.com/electricity-and-magnetism/electric-current.html

16. UnkleRhaukus

maybe electric current is a phasor

17. agent0smith

Hmm, i guess current can be negative, because it does have direction (it can come up like that when using Kirchoff's laws, to find current in loops of a circuit).

18. yrelhan4

http://openstudy.com/study#/updates/4fb98da9e4b05565342e8394 Look what phoneix_rags and chrsimmo have said.. hmm.. scalar i'd say now..

19. yrelhan4

and why it is not a vector even though it has direction... i'll give it to ruchi.. still not 100% sure about what current is.. but scalar looks good to me.

20. yrelhan4

ok another example.. for force on a current carrying wire in a magnetic field F=IdL×B .. here B is a vector.. and dL is a vector. we take the the direction of current to decide the direction of dL.. and it completely depends on what coordinate system we choose.