Q.

A parallel plate capacitor of capacitance 1 μF is charged to a potential difference of 20 V. The distance between plates is 1 μF. The energy density between plates of capacitor is :          [2025]

1 1.8×103J/m3  
2 2×104J/m3  
3 2×102J/m3  
4 1.8×105J/m3  

Ans.

(1)

Energy density u=12ε0E2=12ε0(Vd)2

 u=12(8.85×1012)(20106)2J/m3=1.8×103J/m3