Question

A battery is attached to an ideal parallel-plate capacitor. While the battery remains attached, the two plates of the capacitor are moved further apart to three times the original distance. During this process, the E field inside the capacitor __________ (increases or decreases) by a factor of _________.

Answer 1

The capacitor is still connected to the power supply the potential difference can't change. Moving the plates further apart decreases the capacitance, also reduce the charge stored by the capacitor. E = v/d electric field inversely proportional to distance. If the electric field increases, distance decrease, distance increases electric field also decreases. Three times of original distance, so the electric field increases the factor 3