Electrostatics Question 144
Question: An air filled parallel plate capacitor has capacity C. If distance between plates is doubled and it is immersed in a liquid then capacity becomes twice. Dielectric constant of the liquid is [BCECE 2004]
Options:
A) 1
B) 2
C) 3
D) 4
Show Answer
Answer:
Correct Answer: D
Solution:
$ C=\frac{{\varepsilon _{0}}A}{d} $ ……(i) $ C’=\frac{{\varepsilon _{0}}KA}{2d} $ ……(ii) From equation (i) and (ii) $ \frac{C’}{C}=\frac{K}{2} $
therefore $ 2=\frac{K}{2}\Rightarrow K=4 $
