Question Detail
Question
Two capacitors are identical except that one is filled with air and the other with oil. Both capacitors carry the same charge. What is the ratio of the electric fields E_air/E_oil?
Correct Answer
Option D is the correct answer.
Detailed Explanation
A dielectric (oil) reduces the field for a given charge (E = E_vacuum/K), so E_oil < E_air, meaning the ratio E_air/E_oil is greater than 1.
Hint
Recall that a dielectric reduces the electric field for the same free charge, so compare which field is larger.