Search
In classical physics book of kleppner, i read that An atom can "jump" from one stationary state a to a lower b by emitting radiation with $E_a-E_b$. The frequency of the emitted "package of radi...
I know this is a bit late, but if you still haven't figured it out, here goes: Firstly, let the mass per unit area of the disk be $\sigma = \frac{m}{\pi R^2}$. Consider a small element of area $d...
May it be that there are more than 8/9 planets in our solar system which aren't detectable with the current technologies? Is there any theory suggesting that our solar system has more planets, all...
In the lab I changed the angle the light hits a photoresistor and it doesnt obey Lambert's cosine law the conductivity of the photoresistor drops fast from +-20 to +-30 degrees angle.Why?
I'm interested in knowing the surface temperature of both sides of a double-pane or triple-pane window. Given the R-value of the window, and the air temps outside and inside, how can I calculate t...
The "R value" of insulation is its thermal resistance. It tells you how much of a temperature difference is required to transfer a certain amount of heat power per unit area. The R-value you see ...
As you probably know, one of the postulates Einstein's Special Relativity is based on is that all observers see light in vacuum go at the same speed $c$. Now consider a lamp at rest relative to Jo...
All given metrics are for orthonormal-basis. 2 dimensional spacetime : I saw that Minkowski Metric looks like this : $$\pmatrix{-1 & 0 \\ 0 & 1}$$ or $$\pmatrix{1 & 0 \\ 0 & -1}...
It depends on what you want from your calendar. If you simply want a way to keep track of time, then you can base it on anything you like. The earth spinning on its axis, the moon orbiting the ea...
A particle is subjected to the potential V (x) = −F x, where F is a constant. The particle travels from x = 0 to x = a in a time interval t0 . Assume the motion of the particle can be expressed i...
To understand virtual work you should understand virtual displacement first, The wiki I have linked in first paragraph describes virtual displacement deeply. Usually we write $\delta$ or $d$ to sa...
$$F=F(q,p,t)$$ $$\frac{dF}{dt}=\frac{\partial F}{\partial q}\frac{\partial q}{\partial t}+\frac{\partial F}{\partial p}\frac{\partial p}{\partial t}+\frac{\partial F}{\partial t}$$ $$=\frac{\part...
Modern physics has pretty much dismissed the concept of the ether. Any modern claim that something like the luminiferous aether exists would be up against mountains of experimental results indicati...
Actually $\mathcal O$ is some standard point and $r$ is where potential depends on. $$V(b)-V(a)=-\int_{\mathcal{O}}^B \vec E \cdot d\vec l +\int_{\mathcal{O}}^A \vec E \cdot d\vec l $$ $$ =-\int_{...
Order and disorder aren't scientifically precise terms. In this context, they're an attempt to make the idea of entropy more intuitive. A configuration could appear orderly just by chance, yet be h...
I was wondering what's the physical meaning of Laplace operator. $\vec\nabla$ actually represent a field. I had seen that Laplace operator is written as $\vec \nabla \cdot \vec\nabla=\nabla^2=\Delt...
$x(t)=a\cdot \sin(t\sqrt{k/m})$ is the only solution that satisfies $x(0)=0$. If you then impose $x(c)=0$, you only get solutions for certain values of $k$. These values are the eigenvalues of the ...
The most famous formula of this kind is Bloch's $T^{3/2}$ law: $$M(T)=M_0 \left( 1-\left(\frac{T}{T_c}\right)^{3/2}\right)$$ It is a low-order approximation for the spontaneous magnetization in i...
Suppose we have a gravitational wave which obeys the equation: $[G_{tt}-c^{2}G_{xx}]h_{\mu\nu}=0$ Lets take the case where $h_{\mu\nu}\ne0$ so we are left with the classical wave equation.Suppose...
Are questions that are borderline chemistry on topic? Since there is not a Codidact community for Chemistry (yet?), I thought the next best match would be Physics Codidact. In particular I wanted ...
A computer can store some number $n$ of bits in memory, and it can perform some number $m$ of essential computational operations, such as addition or multiplication, and rewrite those bits to memor...
Suppose we have a arc of charges with some charge density $\lambda(\theta) = sin\theta$.I am using polar coordinates for convenience.But how can I find the direction of the unit vector of the net e...
Pretty much any system where the state of one thing effects the rate of another, and the state of that other thing effects the rate of the first. Surely you can think of a few of those. One examp...
The general formula for a EM wave (solving for the E field) is: where $\varepsilon = \varepsilon _{r}+j\frac{\sigma }{\omega }$ My professor told me that the conductivity of vacuum is 0 so we...
Suppose we perform the double slit experiment , but we fire instead 2 electrons instead of 1. In the double slit experiment performed in the 1920s a interference pattern was observed at the screen...
