Electrostatics Question 87
Question: The capacitance of an air filled parallel plate capacitor is $ 10\mu \mu F $ . The separation between the plates is doubled and the space between the plates is then filled with wax giving the capacitance a new value of$ 40\times {{10}^{-12}}farads $ . The dielectric constant of wax is [AMU 1995]
Options:
A) 12.0
B) 10.0
C) 8.0
D) 4.2
Show Answer
Answer:
Correct Answer: C
Solution:
$ C _{1}=\frac{{\varepsilon _{0}}A}{d} $ and $ C _{2}=\frac{K{\varepsilon _{0}}A}{2d} $
therefore $ \frac{C _{2}}{C _{1}}=\frac{K}{2} $
therefore $ \frac{40\times {{10}^{-12}}}{10\times {{10}^{-12}}}=\frac{K}{2} $
therefore K = 8
