Question

A single point charge is placed at the center of an imaginary cube that has 19 cm long edges. The electric flux out of one of the cube's sides is -2.5 kN·m2/C. How much charge is at the center? .................. nC

Answer 1

The amount of charge at the center is -132.7 nC

Solution:

As per the question:

Electric flux from one face of cube,
`\phi_(E) = - 2.5 kN.m^(2)/C`

Edge, a = 19cm

Since, a cube has six faces, thus total flux from all the 6 faces =
`6* (-2.5) = - 15 kN.m^(2)/C`

Also, from Gauss' law:

`\phi_(E,net) = (1)/(\epsilon_(o))Q_(enc)`

`Q_(enc) = 8.85* 10^(- 12)* - 15* 10^(3)`

`Q_(enc) = - 132.7 nC`