Final answer:
The strength of the electric field in a region where the electric potential is constant is zero.
Step-by-step explanation:
In a region where the electric potential is constant, the strength of the electric field is zero.
This is because the electric field is the negative gradient of the electric potential. If the electric potential is constant, its gradient is zero, which means there is no change in potential with respect to distance. Therefore, there is no electric field in that region.