Differences between two Voltage formulas

In summary, there are two different voltage formulas - one for a point charge and one for an inductor. These formulas represent different concepts and cannot be derived from each other. The two expressions are related through Maxwell's equations. However, it is common for equations describing different phenomena to share a variable. To better understand the significance of these formulas, one can consider what is generating the voltage in each case.
  • #1
sawer
65
2
What is the differences between these two voltage formulas.
1. for a point charge: $$V = k\frac{q}{r}$$
2. for an inductor: $$V(t)= L\frac{di}{dt}$$

Why are there different voltage formulas? Can second one be derived from the first one?
Or do they completely represent different concepts?
 
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  • #2
The two expressions refer to different circumstances; sub-sets of the general case. If you look at Maxwell's equations then you will see how it all ties together.
It is common for equations describing phenomena to share a variable.
 
  • #3
Can you please give some hints
 
  • #4
Just think of the suvat set of equations used for calculations in dynamics. There is always a choice of how to express things in terms of different variables. Are you looking for some extra significance in this?
 
  • #5
sawer said:
Can you please give some hints

Well, what is generating the voltage in each case?
 

1. What are the two most common voltage formulas used in science?

The two most common voltage formulas used in science are Ohm's law (V = IR) and Kirchhoff's voltage law (ΣV = 0).

2. What is the main difference between Ohm's law and Kirchhoff's voltage law?

The main difference between Ohm's law and Kirchhoff's voltage law is that Ohm's law deals with the relationship between voltage, current, and resistance in a single circuit element, while Kirchhoff's voltage law deals with the sum of voltages in a closed loop or circuit.

3. Which voltage formula should I use for simple circuits?

For simple circuits with only one resistor, Ohm's law (V = IR) is the most commonly used voltage formula.

4. When should I use Kirchhoff's voltage law instead of Ohm's law?

Kirchhoff's voltage law (ΣV = 0) is used when analyzing more complex circuits with multiple components, such as parallel or series circuits, where the sum of all voltages in a closed loop must equal zero.

5. Can I use both voltage formulas in the same circuit?

Yes, you can use both Ohm's law and Kirchhoff's voltage law in the same circuit. In fact, they are often used together to solve for unknown variables or to check the accuracy of calculations.

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