Question

Two identical air filled parallel plate capacitors are charged to the same potential in the manner shown by closing the switch $S$ . If now the switch $S$ is opened and the space between the plates is filled with a dielectric of relative permittivity ${\epsilon }_r$ , then

• A. the potential difference as well as charge on each capacitor goes up by a factor ${\epsilon }_r$
• B. the potential difference as well as charge on each capacitor goes down by a factor ${\epsilon }_r$
• C. the potential difference across $A$ remains constant and the charge on $B$ remains unchanged
• D. the potential difference across $B$ remains constant while the charge on $A$ remains unchanged

Answer 1

Answer: (C)

When switch $S$ is opened, capacitor $A$ is still connected with battery. Therefore, potential difference across $A$ remains constant. As $B$ is disconnected from battery, charge on $B$ remain fixed.