A parallel plate capacitor having a plate separation of `2mm` is charged by connecting it to a `300v` supply. The energy density is

Options

A. `0.01J//m^(3)`
B. `0.1J//m^(2)`
C. `1.0J//m^(3)`
D. `10J//m^(3)`

Answer

B

Explanation

Energy density
`=(E)/("Volume")=((1)/(2)CV^(2))/(Ad)`
`=(1)/(2)(epsi_(0)A)/(d xx Ad)xxV^(2)=(1)/(2)epsi_(0)(V^(2))/(d^(2))`
`=(1)/(2)xx8.85xx10^(-12)xx((3xx10^(2))^(2))/((2xx10^(-3))^(2))`
`=(8.85xx9)/(2xx4)xx10^(-12+4+6)`
`overset(.)underset(.)(=)10xx10^(-2)underset(.)overset(.)(=)10^(-1)J//m^(3)=0.1J//m^(3)`