1. The Biot-Savart Law tells us how to calculate the magnetic field due to a current, by adding up little contributions from Idl sections of the current. The contribution to the B-field changes with distance from the current to the point in space we want to know B. What is that relationship?

1/r2

r

1/r3

1/r

2. There's a vector operation involved with the Biot-Savart Law. What is it?

A cross-product

A derivative

A dot-product

A summation

3. The magnetic field for an infinitely long straight wire changes with distance from the wire. What is that dependence?

1/r2

r

1/r

1/r3

4. The magnetic field lines for an infinitely long straight wire point in what direction?

They point directly away from the wire.

They circulate around the wire.

They point along the same direction as the wire.