A) 4
B) 8
C) 2
D) 6
Correct Answer: C
Solution :
The capacitance of air capacitor \[C=\frac{{{\varepsilon }_{0}}A}{d}\] When a dielectric slab of thickness \[t=d/2\] is inserted between plates, the capacity becomes \[C=\frac{A{{\varepsilon }_{0}}}{d-d/2\,\left( 1-\frac{1}{K} \right)}\] \[\frac{4}{3}\frac{A{{\varepsilon }_{0}}}{d}=\frac{{{\varepsilon }_{0}}A}{d-d/2\left( 1-\frac{1}{K} \right)}\] \[3d=4d\left( 1-\frac{1}{2}+\frac{1}{2K} \right)\] \[3=4\left( \frac{1}{2}+\frac{1}{2K} \right)\] or \[\frac{4}{2K}=3-2\] or \[K=2\]You need to login to perform this action.
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