Answer:
B = 0.159 T
Step-by-step explanation:
Given that,
Current, I = 0.38 A
The average velocity of the electron,

The average magnetic force on the electron,

We need to find the flux density B of the magnetic field. We know that the magnetic force is given by :

Put all the values,

So, the required flux density of the magnetic field is 0.159 T.