Two uniformly charged spherical drops are each at potential V and have capacitance C. They coalesce to form one larger drop. Find the potential of the larger drop in units of V.
Physics · Capacitor
JEE Advanced

Question

Two uniformly charged spherical drops are each at potential V and have capacitance C. They coalesce to form one larger drop. Find the potential of the larger drop in units of V.

G1 Physics · Accepted Answer

The new radius is R′=2¹ᐟ³R, so C′=2¹ᐟ³C. Total charge is 2CV. Therefore V′=(2CV)/(2¹ᐟ³C)=2²ᐟ³V≈1.59V. Numeric answer: 1.59.