A general rule for estimating the capacitance C of an isolated conducting sphere with radius r is C(in pF) r (in cm). That is, the numerical value of C in pF is about the same as the numerical value of the sphere's radius in cm.

a) Modeling the human body as a 1-m-radius conducting sphere, use the given rule to estimate your body's capacitance (in pF). i calculated it to be 100 pF this is correct

b). While walking across a carpet, you acquire an excess "static electricity" charge Q and produce a 0.5-cm spark when reaching out to touch a metallic doorknob. The dielectric strength of air is 30 kV/cm. Use this information to estimate Q(in ^oC).

Express your answer with the appropriate units.