Question

The radius of the earth is 6381 km. The capacitance of the earth is:

• A. $709\times {10}^{9}F$
• B. $709\times {10}^{-9}F$
• C. $709\times {10}^{-12}F$
• D. $709\times {10}^{-6}F$

Answer 1

The correct option is D $709\times {10}^{-6}F$

We know voltage of series $V=\frac{kQ}{R}$
$C=\frac{Q}{V}$

$C=\frac{Q}{kQ}$

$\therefore C=\frac{R}{k}$

$C=\frac{6381\times {10}^3}{9\times {10}^9}$

$C=709\times {10}^{-6}F$