Question

The maximum electric field that can be held in air without producing ionisation of air is ${10}^{7}V/m$. The maximum potential therefore, to which a conducting sphere of radius 0.10 m can be charged in air is :

• A. ${10}^{9}V$
• B. ${10}^{8}V$
• C. ${10}^{7}V$
• D. ${10}^{6}V$

Answer 1

Answer: (D)

${10}^{6}V$

Given, electric field, $E={10}^{7}V/m$ and radius , $r=0.10m$

Let if V be the maximum potential, then $E=V/r$

or $V=Er={10}^7\times 0.10={10}^{6}V$