Q29. a capacitor is made of two conducting spheres each of radius r and covered by a thin insulating sheet. they carry charge q and-q respectively and their cen

Q29. A capacitor is made of two conducting spheres each of radius R and covered by a thin insulating sheet. They carry charge Q and-Q respectively and their centers are separated by a distance d. If the capacitance of this capacitor is given by C O/ where Vis the potential difference between the two spheres then (a) Cis maximum when d is infinity (b) Cis maximum when d approaches 2R (C) Cdoes not depend on d (d) Cis maximum for d=4R