Question

1) A magnetic field intensity vector H has only Z component given by H_Z= 3xcosβ+6ysinα. If the field is invariant with time. What is the expression for the current density vector J?

(α and β are constants).

2) An electron whose Q= -1.602*10^-19 C, is moving with a velocity of 10⁶m/s in the a_x direction in a magnetic field B=0.2a_x-0.3a_y+0.5a_z wb/m². What is the electric field present if no net force is applied tot he electron. ( Note = Total force= QE+Q(VXB))

Answer 1

Given :

To find Current Density vector:

Since by Maxwell's equation

where J is current density.

and   

Since only z- component of H is present so  

So, the term

will not be present in   .

Therefore,

Given:

  Charge (Q) on electron :

Velocity of electron in the direction of :

Magnetic field (B):

No net force is applied to the electron .So,

So,