Answer:
122.84 J
Explanation:
Since plate is square, area, A is given by [tex](8.7/100)^{2}=0.007569m^{2}[/tex]
The distance between plates, d, is given in the question as 2mm=0.002m
Charge on plate, Q, as given in the question is 240 [tex]\mu c[/tex]
Assuming mica dielectric constant, k of 7
Capacitance, C is given by
C=[tex]\frac {k\epsilon_{o}A}{d}=\frac {(7)(8.85*10^{-12})(0.007569)}{0.002}=2.34*10*^{-10}F[/tex]
Stored energy, E is given by
E=[tex]\frac {Q^{2}}{2C}=\frac {(240*10^{-6})^{2}}{2*(2.34*10^{-10})}=122.84J[/tex]
Therefore, the stored energy is 122.84 J