Answer:
[tex]D=2.996\times 10^{-2} m[/tex]
Explanation:
*Assume the parallel disks have equal diameters.
Given the electric strength as [tex]1.0\times 10^5 N/C.[/tex] transferring [tex]3.9\times 10^9[/tex] electrons, the disk's Area can be calculated using the formula:
[tex]E=\frac{\eta}{\epsilon_o}=\frac{Q}{A\epsilon_o}\\\\A=\frac{Q}{E\epsilon_o}\\\\=\frac{(3.9\times 10^9)\times (1.6\times10^{-19})}{(1.0\times 10^5 )\times (8.85\times10^{-12})}\\\\A=7.0508\times 10^{-4} \ m^2[/tex]
#We now calculate the disks diameter:
[tex]A=\pi(D/2)^2\\\\2\sqrt{\frac{A}{\pi}}=D\\\\=2\sqrt{7.0508\times 10^{-4}/\pi}\\\\D=2.996\times 10^{-2} \ m[/tex]
Hence, the diameter of the disks is [tex]D=2.996\times 10^{-2} m[/tex]
