Current is a scalar or vector

J is the current density and Ne is the external normal unit vector to Σ. You see that, by changing the orientation of the surface, the normal vector changes its sign . Now to understand this we have to go to the definition of vector. Can mathematicians be any more neat? Strictly speaking, a current in some volume is worked out be calculating the rate of change of charge .

It is somewhat like the difference between speed and velocity.

You must have got the doubt that how can electric current be scalar quantity when it has direction and magnitude both.

Yes, the current has both direction and magnitude both but we call it scalar quantity because the direction in which the current flows is same. The current moves in the same direction from . Secondly, current does not follow the vector law of addition. Let us take an example:- In the above figur.

I see in several physics papers and articles current , current density represented by vectors. Can some one clarify this point with an example and show that current does not obey vector law of . And the reason is, because it is.

The two equations are equivalent in magnitude as shown below. While we define vectors ,we say that the quantity should follow vector algebra,but current . Those quantities which have magnitude as well as direction, but do not follow the triangle laws of vector addition are known as tensor quantities. But such arrows are not vectors because they do not . The scalar current density is given by.

It's related to the amount of current cutting some small vector at any given point. Talking about electric charge it fails to obey the law of vector addition.

Currents do not have direction. A scalar has magnitude with zero direction ie. According to this definition should not pressure and current be vectors since both are associated with some definite direction? In some places they are treated as scalars .