We know that an operator is Hermitian when: $\langle f|\hat{O}g\rangle$ = $\langle \hat{O} f|g\rangle$ Parity operator in 1D is simply defined as: $\hat{\Pi} f(x) = f(-x)$ I don't know anything about the eigenvalues of parity operator (that is asked in the next problem). How can I show it is Her...

So I have this (possibly dumb) question about the implications of the 2nd law of Thermodynamics to the use of Renewable energy for the world, so please bear with me. Here goes: Apart from the finiteness of fossil fuels (FFs), which is obviously an issue, the main problem for sustainability in bur...

I heated my milk cup in the microwave today and noticed that the cup was hot but not the handle. Even if I heat it too much , cups handle temperature remains the same. How is that possible?

I'm no expert on string theory, but I've been reading about it. I've been quite surprised because of how it appears to be inconsistent with observations, but hasn't been rejected yet. Examples: On the cosmological implications of the string Swampland Criterion 2: The current B-mode constraint $\...

Is the intensity or brightness of light the same idea? In other words, when we are observing Malus's law, are we looking at the "brightness" of light? If they are not the same quantity, how can we qualitatively see the intensity of light and distinguish it from the qualitative visualization of br...

According to this the plasma of a plasma torch can reach up to 28,000 degrees Centigrade. How is it possible for the plasma to reach a temperature much higher than that of The Sun's surface and not completely burn and melt everything in a mile radius? Even with the poor heat conductivity of the a...