Electrostatics Question 85
Question: The capacity of a parallel plate condenser is $ 10\mu F $ without dielectric. Dielectric of constant 2 is used to fill half the distance between the plates, the new capacitance in $ \mu F $ is [EAMCET (Engg.) 1995]
Options:
A) 10
B) 20
C) 15
D) 13.33
Show Answer
Answer:
Correct Answer: D
Solution:
$ C=\frac{A{\varepsilon _{0}}}{d}=10\mu F $
$ C _{1}=\frac{A{\varepsilon _{0}}}{d-t+\frac{t}{k}}=\frac{A{\varepsilon _{0}}}{d-\frac{d}{2}+\frac{d}{2k}}=\frac{A{\varepsilon _{0}}}{\frac{d}{2}( 1+\frac{1}{2} )}=\frac{4}{3}.\frac{A{\varepsilon _{0}}}{d} $
$ C _{1}=\frac{4}{3}\times 10=13.33\mu F $
