Question

The dielectric strength of air is $3\times {10}^6$V /m. A parallel plate air capacitor has area $20cm$${}^2$ and plate separation $1$ mm. Then maximum r.m.s. voltage of an A.C. source which can be safely connected to this capacitor is

• A. 212.2 V
• B. 21.22 V
• C. 2.122 V
• D. 2122 V

Answer 1

The correct option is D 2122 V

Given : $E=3\times {10}^6$ V/m $d=0.001$ m

Thus maximum r.m.s voltage $V_{max}=\frac{Ed}{\sqrt{2}}=\frac{3\times {10}^6\times 0.001}{\sqrt{2}}$

$⟹$ $V_{max}=2122$ V