The force of a test charge would be doubled if the electric field is doubled.
Answer: Option A
Step-by-step explanation:
Electric field is the region or range up to which a charge particle will have its influence of electric energy on another charged particles. So the experienced force by the test charge up to a certain range is defined as the electric field of that charged particle.
This means that the electric field strength is inversely proportionate to the test charge and directly proportionate to the force acting on the test charge. As ,

So, force will be product of electric field strength with test charge. Thus,

So, if there is increase in the electric field, then there will be increase in the force of the test charge. Thus, if the electric field is doubled thereby the force of a test charge will also be doubled.