1. The problem statement, all variables and given/known data I have seen earth and ground used interchangeably. However, there appears to be some distinction with regards to reference point ground and earth ground. My textbook used an example of a loaded voltage divider and examined how the voltage across certain resistors can be measured to be positive or negative depending on how we define our ground (at-least thats what I gathered from it). This is because, regardless of where we place the ground, that location (node) by definition is at zero volts. So my question is, lets say we have a circuit with a single power supply. Is earth ground always connected to the negative terminal of the power supply while reference point ground is generally thought of as a ground that does not have to be connected to the negative terminal of the power supply? If I am wrong, can someone please provide a brief explanation as to the differences between the two?