The Grainger College of Engineering
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Is Current a Scaler or Vector Quantity?

Most recent answer: 05/03/2015

Q:
Our teacher asked us find the authentic reason behind why current is a scalar quantity , so my first question on this forum would be "Why current is a scalar quantity when It has both direction and magnitude ?"
- Reckon (age 20)
Pakistan
A:

Hello Reckon,

There is a bit of a problem here.  Your teacher may have been only thinking of the value of a current flowing in a wire as read on an ammeter.  In that case current is just a scaler number.

However the wire in which the current flows has a direction.   Any magnetic field associated with the current will have a direction related to the Biot-Savart Law:

                  \mathbf B = \frac{\mu_0}{4\pi} I \int_C \frac{d\mathbf l \times \mathbf{\hat r}}{r^2}

Here, dl is a vector element pointing the direction of a wire element.   So in this sense current is indeed a vector quantitiy.

LeeH


(published on 05/03/2015)

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