# Homework Help: Which describes the magnetic flux through a section of a loop?

1. Apr 6, 2012

### McAfee

1. The problem statement, all variables and given/known data

Which describes the magnetic flux through a section of a loop?

A. It is a vector that is directed outward through the section.
B. It is a vector that is directed inward through the section.
C It is a vector that is tangent to the section.
D. It is a scalar.

2. Relevant equations

http://edugen.wileyplus.com/edugen/courses/crs4957/halliday9118/halliday9088c30/math/math114.gif

3. The attempt at a solution

I think the answer is D because there is no direction when solving for magnetic flux.

I just want verification, thank you.

2. Apr 6, 2012

### McAfee

Now I'm thinking that the answer is A.

3. Apr 6, 2012

### Staff: Mentor

If you look up the defining calculation for the magnetic flux you should have your answer; does the calculation produce a vector or a scalar?

4. Apr 6, 2012

### McAfee

Wow. Thanks gneill. I think I know the answer.

Phi = B.A

It has SI units of the weber (Wb) which is a tesla metre squared (Tm^2) and is a scalar

Am I right?

5. Apr 6, 2012

### Staff: Mentor

Yup. Equivalent units are also V-s (Volt-second). This becomes important when you start looking for induced emf's due to rates of change of flux