# All Questions

60 views

### How does curved spacetime cause motion revisited

There was a previous question titled "Why would spacetime curvature cause gravity?" asked March 10, 2014. The answer given was essentially that since the time component of an object in curved space ...
1k views

### What is a bulk phase transition?

I have been able to google "bulk phase transition" and get plenty of results that verify that something called a bulk phase transition exists, however, I cannot seem to find a precise definition of ...
60 views

### Does limiting to infinity violate laws of physics?

It is noteworthy that one cannot simply divide any length more than the Planck-length. If so, one cannot simply divide any volume more than the $(Planck-length)^3$. So if I want to find the limit of ...
976 views

### How do we prove the existence of a multiverse?

How do we prove that a multiverse exists? Scientists are talking about our universe not being the only universe, but even if that is true, how can we prove the existence of multiverse? We are being ...
425 views

### Actual meaning of “Gravitational Potential”?

In a gravitational field, the gravitational force acting on a body (of mass m) at a point x metres away from the attracting body (of mass M) is $\frac{GMm}{x^2}$. Integrating this force from a point ...
138 views

### What are the virtual particles generated during the Hawking radiation?

What are the virtual particle pairs generated during the Hawking radiation? If a photon is emitted by Hawking radiation, what is its negative energy partner which fell into the black hole? Does it ...
34 views

### To what height does the ball rebound and what is the velocity of the struck block after impact? [on hold]

Here is the problem. I have tried it four different times, and I will show my most recent work. [![enter image description here][3]][3]
26 views

### Volume integral of pressure interpretation

If you have a fluid with with pressure field $p$ what is the physical significance of the the volume integral of the pressure $\int_V p dV$?
8 views

### How actually sign reversal of output signal and the input signal takes place in case of amplification of transistor? [migrated]

How actually sign reversal of output signal and the input signal takes place in case of amplification of transistor? I am a class 12 student so make me understand accordingly.
22 views

### Why does small change in Base current causes a larger change in collector current in case of transistors? [on hold]

Why does small change in the base current causes larger change in the collector current. That is say if I increase the base current buy a small amount why the collector current increases by a very ...
12 views

### What do you actually mean by DC voltage again and AC voltage gain? [migrated]

What do you actually mean by DC voltage gain and AC voltage gain? I know their formulas but I do not understand what they actually are? That is, basically I do not understand what is their ...
14 views

### Help me select a motor! [on hold]

I am having trouble selecting a motor to power a crank-rocker system I am building. I honestly don't know much about DC motor selection so would you guys be able to help me out? I am looking for a 12 ...
147 views

### How can I simulate a model electronic hole?

Suppose I can solve time-dependent Schrödinger equation for several 1D particles (currently 3). I'd like to see, what an electronic hole is and how it behaves — in a series of numerical experiments. ...
24 views

### $\rho g h$ and shape of container inconsistency?

The Scenario Suppose I have a cylindrical beaker and a conical flask (which cross-sectional area is bigger at the bottom), each located on an identical digital weight scale. Both of them have the ...
36 views

### What happens if an object stops orbiting the sun? [on hold]

What would happen if an object (like a space ship) was to stop its orbit around the sun. would time slow down with that object (the same way time sped up for the characters in that great film ...
311 views

### How is current produced in semiconductors or metals?

I think current is the movement of electrons through the wire or semiconductor, thus when I press the switch of the light bulb the electrons go from positive part to tungsten and light is produced. ...
29 views

### Why is it useful to study spatially inhomogeneous spacetimes? [on hold]

There are many scholars who have dedicated their efforts towards finding solutions to the Einstein Field Equations that are spatially inhomogeneous. Current cosmological observations indicate that on ...
315 views

### Magnetic scalar potential far above a magnetic film

The situation I am looking at is a magneto-static problem of a finite magnetic film with magnetization $\bf{M}$. I would like to find the the magnetic field far above the plate. My expectation is that ...
278 views

### What is the general relativity explanation for why objects at the center of the Earth are weightless?

The idea that as you move through the earth you get a symmetric cancelling of gravitational acceleration which approaches zero acceleration due to gravity at the center of the earth makes a lot of ...
13 views

### What do you actually mean by DC current gain and a AC current gain in transistors [duplicate]

What do you actually mean by DC current again and AC current gain? I know there for formulas but I did not understand what actually they are , what is the significance. So basically I do not ...
49 views

### Speed of different colours of light [duplicate]

Speed of light is different for different colours. What does the speed of a particular colour of light depend on? Which colour of light has the highest speed?