Q92

$$\begin{gathered} \mathbf{92}\mathbf{.} \mathrm{The} \mathrm{electric} \mathrm{potential} \mathrm{on} \mathrm{the} \mathrm{surface} \mathrm{of} \mathrm{a} \mathrm{sphere} \mathrm{of} \mathrm{radius} \mathrm{R} \mathrm{due} \mathrm{to} a \mathrm{charge} 3 \times {10}^{-6} \mathrm{C} \mathrm{is} 500 \mathrm{V}. \mathrm{The} \mathrm{intensity} \mathrm{of} \mathrm{electric} \mathrm{field} \mathrm{on} \mathrm{the} \mathrm{surface} \mathrm{of} \mathrm{the} \mathrm{sphere} \mathrm{in} (\mathrm{N} {\mathrm{C}}^{-1}) \mathrm{is} \\ \left[\frac{1}{4{\mathrm{\pi \epsilon }}_0} = 9 \times {10}^9 \mathrm{N} {\mathrm{m}}^2 {\mathrm{C}}^{-2}\right] \\ \left(\mathrm{a}\right) <10 \left(\mathrm{b}\right) >20 \\ \left(\mathrm{c}\right) \mathrm{between} 10 \mathrm{and} 20 \left(\mathrm{d}\right) <5 \end{gathered}$$