Electrostatics Question 6
Question: Which one statement is correct? A parallel plate air condenser is connected with a battery. Its charge, potential, electric field and energy are$ Q _{o},\ V _{o},\ E _{o} $ and $ U _{o} $ respectively. In order to fill the complete space between the plates a dielectric slab is inserted, the battery is still connected. Now the corresponding values$ Q,\ V,\ E $ and$ U $ are in relation with the initially stated as [IIT 1985]
Options:
A) $ Q>Q _{o} $
B) $ V>V _{o} $
C) $ E>E _{o} $
D) $ U>U _{o} $
Show Answer
Answer:
Correct Answer: A
Solution:
Capacitance will be increased when a dielectric is introduced in the capacitor but potential difference will remain the same because battery is still connected. So according to q = CV, charge will increase i.e. $ Q>Q _{0} $ and $ U=\frac{1}{2}QV _{0},U _{0}=\frac{1}{2}Q _{0}V _{0} $
therefore $ Q>Q _{0} $ so $ U>U _{0} $
