At what distance from a point charge of 8.0 μC would the electrical potential be 4.8 × 104 V? (ke = 8.99 × 109 N⋅m2/C2)

Avolume of 2.65 m3 of air in a rigid, insulated container fitted with a paddle wheel is initially at 264 k, 5.6 bar. the air receives 432 kj by work from the paddle wheel. assuming the ideal gas model with cv = 0.71 kj/kg • k, determine for the air the amount of entropy produced, in kj/k