A flat square sheet of charge (side 50 cm) carries a uniform surface charge density. An electrons0.5 cm form a point near the center of the sheet experiences a force of `1.8xx10^(-12)N` directed away from the sheet. Determine the total charge on the sheet.

Answer

`-50 muC`

Explanation

Electron is 0.5 cm from the sheet of charges and is far away from the edges of the sheet. Therefore, the sheet looks effectively infinite.
`E=(sigma)/(2 epsilon_(0))=(q)/(2 epsilon_(0)A) or F=-eE=-e((q)/(2 epsilon_(0)A))`
`q=-(2 epsilon_(0)AF)/(e)`
`=(2(8.854xx10^(-12))xx(0.5)^(2)xx(1.8xx10^(-12)))/(1.6xx10^(-19))`
`=-50 muC`.