Final answer:
The magnitude of the electric field can be found by dividing the force acting on a charge by the magnitude of the charge itself. In this case, the magnitude of the electric field is 2 N * mC.
Step-by-step explanation:
The magnitude of an electric field can be calculated by dividing the force acting on a charge by the magnitude of the charge itself. In this case, a force of 6 N acts on a charge of 3 mC. The magnitude of the electric field can be found using the formula: Electric field = Force / Charge. Plugging in the given values: Electric field = 6 N / 3 mC = 2 N * mC.
Therefore, the correct answer is B. 2 N * mC.