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

Options

A. B is perpendicular of v
B. B is parallel to v
C. It obeys inverse cube law
D. It is along the line joining the electron and point of observation

Answer

B

Explanation

In Biot-Savart’s law, magnetic field B|| `idl xx r`and idl due to flow of electron is in opposite direction of v and by direction of cross product of two vectors
`B bot v`.