Question

Two identical air filled parallel plate capacitor 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 the 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

The correct option is C the potential difference across A remains constant and the charge on b remains unchanged

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 remains fixed.