We have a voltage source of 5 V and a resistor of 100 Ω is connected to it. The other end of the resistor is connected nowhere. To simplify terminal “A” of resistor is connected to 5 V & Terminal “B” is not connected anywhere. So my questions are
- What will be the Voltage value at the Terminal “B” of the resistor? and How?
- Will there be a decrease in Voltage from 5 V or it remains 5 V on the both terminals of the resistor?
- What is Voltage? Is it Voltage at the Terminal “B”? or it’s 5 V – Voltage at terminal “B” ?
Best Answer
Let's turn your word picture into a real picture so we can see what's happening
simulate this circuit – Schematic created using CircuitLab
Voltage is always measured between two points, so when we quote the voltage of a single point, it's always understood that we are measuring the difference to some reference point.
I've taken the liberty of adding the ground or '0V' symbol. You've told us that 'A' is at 5v, which implies that you're taking the negative terminal of your power supply as your 0V reference.
No current flows through R1, so the voltage across it is zero. This means that B is also at 5v.
Voltage is a potential. A good analogy is 'vertical height' in earth's gravity field, as far as energy goes.
In fact, it's such a well ingrained analogy that you'll notice I drew the diagram with height up the page to represent voltage. Most electronic engineers will do this, as it makes any schematic easier to understand.