Question

Two infinitely long parallel plates of equal areas, $6\,cm^2$, are separated by a distance of $1\, cm$. While one of the plates has a charge of $+ 10\, nC$ and the other has $-10\,nC$. The magnitude of the electric field between the plates, if $\varepsilon_0 = \frac{10^{-9}}{36 \pi } F/ m $ is

• A. $0.6 \,\pi \, kV/m$
• B. $6 \,\pi \, kV/m$
• C. $600 \,\pi \, kV/m$
• D. $60 \,\pi \, V/m$
• E. $6 \,\pi \, V/m$

Answer 1

Answer: (B)

We know that,
$E =\frac{ V }{ d }$
$=\frac{\frac{ q }{ C }}{ d }$
$E =\frac{ q }{\varepsilon_{0} A }$
$=\frac{10^{-8} \times 36 \pi}{10^{-9} \times 6 \times 10^{-4}} V / m$
$=6 \pi \times 10^{3}$
$=6 \pi kV / m$.