What is the electric field at a point 0.450 m to the left of a -5.77*10^-9 C charge? Include a or - sign to indicate the direction the field.

May someone explain how to do this question?

Agas initially at p1 = 1 bar and occupying a volume of 0.5 liter is compressed within a piston–cylinder assembly to a final pressure p2 = 4 bar. (a) if the relationship between pressure and volume during the compression is pv = constant, determine the volume, in liters, at a pressure of 3 bar. (b) repeat for a linear pressure–volume relationship between the same end states. reference

Which feature of a heating curve indicates a change ofn state