# Tag Info

Accepted

### On constants that maintain proportionality

I don't quite understand the greater meaning behind this. Why does the universe work this way? Join the club, friend. Physics can only supply the "why" to the point of deriving general ...

### Notation: units with negative exponents

It doesn’t really matter too much, since it’s just a notational convention. But in some cases you can have fractional or even irrational exponents on the units, in which case the slash notation is ...

### Notation: units with negative exponents

RC_23 asked: "I am assuming that some journals, publishers, and authors require or prefer..." I've seen different notations in the same journal, but you have to keep it consistent within ...
Accepted

### What is stopping optical clocks from redefining the second?

You really shouldn't rush decisions like this. Time keeping is arguably the oldest branch of science, and it usually takes a long time for any changes to the way that people keep time to be decided ...

### Electric field definition

If we place a small 'test' charge, $q$, in an electric field, we find that the force, $\vec F$, that it experiences due to the field is proportional in magnitude to $q$. Therefore if we divide $\vec F$...
Accepted

### Thermal expansion: why in Celsius and not in Kelvin?

No, it is perfectly fine in Kelvins too. You have just mistaken the formula. Basically, when you see a $\Delta,$ there is very high chance that this is a subtraction of two things. What the question ...

### Defining the second by an alien civilization

In the SI system, frequency is measured in Hz. Radiation produced by the transition between the two hyperfine ground states of cesium has a frequency of 9192631770 Hz, by definition. This number was ...

### What exactly is kg?

according to its definition, it is the amount of matter contained in an object. This is incorrect. The actual definition of the kilogram is The kilogram, symbol $\mathrm{kg}$, is the SI unit of mass....

### Is Coulomb written/found on any object/product as its unit?

Coulomb is used wen you have an object wich is charged. du you know what a capacitor is? Or did you do any electro static in class, like a charged sphere? Than you measure the charge in Coulomb. If ...
The extract that you have copied is very confusing. $\log_{10}(P_1/P_2)$ is not the bel, but the relative power expressed in bel(s). If you wanted a definition of the bel (hardly ever sought) it ...
$s^{-1}$ and $\text{rad}\>s^{-1}$ are not equivalent, note that $1s^{-1}$ implies that one "something" is happening every second, whereas $1 \text{rad}\>s^{-1}$ implies specifically ...