An empty 20 pF capacitor is charged to a potential difference of 40 V. The charging battery is then disconnected, and a piece of Teflon with a dielectric constant of 2.1 is inserted to completely fill the space between the capacitor plates.
What is the new capacitance of the condenser?
Answer & explanation
Correct answer: option 2
$C'= kC = 2.1 \times 20pF = 42pF$