Biot-Savart law indicates that the moving electrons (velocity `vecv` ) produce a magnetic field `vecB` such that

Options

A. `vec(B) _|_vec(v)`
B. `vec(B) || vec(v)`
C. it obeys inverse cube law.
D. it is along the line joining the electron and point of observation.

Answer

A

Explanation

Magnetic field produced by charges moving with velocity `vec v`, at a distance r is `vecB = (mu_(0))/(4pi). Q(vecv xx hatr)/r^(2)`
Therefore `vecB bot vecv`.