Final answer:
The magnitude of the magnetic field is approximately 0.333 T.
Step-by-step explanation:
When an electron moves perpendicular to a uniform magnetic field, it experiences a centripetal force due to the magnetic force acting on it. The centripetal force is provided by the magnetic force, given by the equation
.
The magnetic force is also given by the equation
. Setting these two expressions for
equal to each other, we get

Solving for
Substituting the given values
kg, charge of an electron
we calculate

Therefore, the magnitude of the magnetic field is approximately 0.333 T. This calculation demonstrates the relationship between the centripetal force experienced by the electron and the magnetic force acting on it in a uniform magnetic field.