We administered several open-ended questions to students after electrostatics is covered in an electricity and magnetism class at a private Mexican university. In the first part, the objective is to compare students' responses on electric field concept questions in the presence of charges and conductors to those in the presence of charges and insulators. In the second part, the objective is to analyze the difference in responses when the context is changed. This report compares students' answers to electric field concept questions while changing from abstract objects, i.e., point charge, non-conducting sphere; to already-used real materials in lab, i.e., charged tape, non-conducting pencil. Lastly, the objective is to analyze whether a guided question helps students to better answer electric field questions. This study compares students' responses to electric field concept questions with no guidance to responses to guided questions and the degree of guidance.