A parallel-plate capacitor is formed from two 5.0cm -diameter electrodes spaced 2.9mm apart. The electric field strength inside the capacitor is 5.0 *106N/C.
What is the charge (in nC) on each electrode?
Capacitance C of a parallel palte capacitor is given by C = KeoA/d
where A = area = pi r^2,
e0 = constnat = 8.85*10^-12,
d = distance between the plates,
K = dieelctric constant (=1 for air)
Chareg Q = CV where V = Volatge
also EF E = V/d
so E = Q/eoA
charge Q = E eo A
Q = 5e6 * 8.85e-12 * (3.14* 0.025*0.025)
Q = 86.84 nC