The electrons in a beam are moving at 2.8 ×

108 m/s in an electric field of 17000 N/C.
What value must the magnetic field have if
the electrons pass through the crossed fields
undeflected?
Answer in units of µT

1 answer

q v B = q E, therefore
B = E/v

If E is in N/C and v is in m/s, the B field will be in Teslas