Two hollow plastic globes of radius 4.50 cm and 8.40 cm are concentric with each other. The globe of radius 4.50cm has a charge of -12.5 nC distributed evenly on its surface. Similarly, the other globe has a charge of +8.25 nC evenly distributed over its surface. If the electric potential is zero at an infinitely large distance, determine the resultant electric potential from the two globes at i) r = 0 cm ii) r = 6.00 cm iii) r = 8.40 cm.