-1
votes
3answers
1k views

Physics book recommendations for transition to PhD study

Now in the end of my MSc in physics I've been contemplating in enrolling in a Phd in theoretical physics. Before that I think I would do best to re-study some subjects. My question is then, what books ...
-1
votes
4answers
388 views

What forces are at play when molecules wiggle (due to heat)?

What forces are at play when molecules wiggle (due to heat)? Or in other words, What makes them move?
-1
votes
3answers
3k views

Relation between Newtons and Kilograms

Work is expressed as W=F*d, where the F is in Newton, d is in meters and result ...
-1
votes
4answers
117 views

Why uncharged particles do not feel the Lorentz force? [closed]

Why uncharged particles do not feel the Lorentz force? Please do not answer with the formula $ \vec F = q\left( \vec E + \vec v \times \vec B \right) $. Edit after an answer which is an circular ...
-1
votes
3answers
313 views

Differences between wavefunction, probability and probability density?

I am trying to understand the differences between wavefunction, probability and probability density. There are different definitions on the internet. For example: ...
-1
votes
2answers
68 views

Is fission reaction considered natural or artificial? [closed]

As I learned, nuclear fission doesn't occur without the control of a human made nuclear reactor, by hitting a neutron to a fissile isotope. Thus, the fission reaction is considedred as a part of ...
-1
votes
1answer
125 views

Why are laws of physics always of product forms?

A first observation is that all the extant laws of physics are of product forms. This phenomenon is somewhat intriguing. The question is: why do law of physics always take, instead of a sum of two ...
-1
votes
1answer
135 views

why countries can't make nuclear bombs? [closed]

Somehow when I google about the nuclear bombs I find a lot of books and resources that seem to explain everything about how those bombs are made. But sometimes I often hear that countries that want to ...
-1
votes
1answer
106 views

Apply the Heisenberg Equation to the Hamiltonian [closed]

$\frac{d}{dt}$$\hat{H}$ = $\frac{i}{\hbar}$$[\hat{H},\hat{H}]$ +$\frac{\partial{\hat{H}}}{\partial{t}}$ That's as far as I've got. I do not know much about the Heisenberg equation or even what it ...
-1
votes
1answer
290 views

Commutator with Pauli spin matrices and the momentum operator

How is $\left[\vec\sigma \cdot \vec p, \vec \sigma \right]$ proportional to $\vec \sigma\times \vec p$, where $\sigma$ are the Pauli spin matrices and $p$ is the momentum operator?
-1
votes
1answer
108 views

Can a wave exist on the “face” of a wave?

It would seem that this would be possible with waves in water. What about other waves Clarification: Given a wave starting from a point of impact, in water, at: Time 0:00 and xyz 0,0,0 and the ...
-1
votes
3answers
2k views

Collision between electron and proton?

What would happen if an electron collided with a proton such that the two do not collapse? Would the two become a unit, or would some force prevent them from bonding thus forcing the electron to orbit ...
-1
votes
2answers
185 views

How many mirrors placed perpendicular to each other shall make a light ray completely reverse its path?

The answer is 3. But according to me 2 shall also work in 2 Dimensions? Does anyone has a theoretical proof?
-1
votes
2answers
228 views

How does artificial gravity reduction (weightlessness) work on Earth?

Some of us have been to those amusement park/carnival/theme park rides where you enter some capsule/machine, and you will float, etc. There is also some other thing where you go inside a big room ...
-1
votes
2answers
161 views

Scaling: Gravity and Friction

I understand how doubling the length of a shape quadrupes it's area and the analog in 3 dimensions. My question however relates to other physical quantities, for example gravitational field strength. ...
-1
votes
1answer
88 views

Dark Energy Explanation Found [closed]

It's my sincere request to this Physics forum that if i am wrong (which has the least possibility atleast from my side) just reply "wrong" so that i can move on futher. I know personal theories are ...
-1
votes
1answer
118 views

Why nuclear tests move under ground since 1964?

According to this database: http://www.ga.gov.au/oracle/nuclear-explosion.jsp Since 1962, 99% of USA Nuclear tests was underground. Since 1964, 99% of Soviet Nuclear tests was underground. Is it ...
-1
votes
5answers
4k views

Is it possible to generate electricity using a water tower?

Is it possible to build a water tower that will provide enough pressure to run an electricity generator? A water pump can be used to send water up to the tower. The water pump can be powered by solar ...
-1
votes
3answers
1k views

Right hand rule to measure direction of electric field [closed]

The diagram: a positive plate is on the left of the page and a negative plate is on the right. The velocity of the particle is going down the page. So, with a right hand rule, I would point my thumb ...
-1
votes
2answers
909 views

How to determine Center of Gravity? [closed]

I came across this question while having conversation with one person. We know that Center of Gravity of a solid cube is at the intersection of connecting the opposite vertex of the cube. Suppose, you ...
-1
votes
2answers
480 views

How to visualize a 3D scalar function? [closed]

In physics, we regularly deal with observables, which are functions $f(x,y,z)$ of the position vector $\vec r = (x,y,z)$. How, do you plot such a function? For functions $y=f(x)$ of 1 parameter, we ...
-1
votes
1answer
3k views

Can I use AA batteries to charge iPhone? [closed]

Technically, 4 AA batteries will give out ~5V, which is equivalent to USB. Can you use 4 AA batteries to charge an iPhone, without messing up the Li-Ion cells used on iPhone? So my question really ...
-1
votes
2answers
249 views

Is Dark Energy converted to Gravitational Potential Energy?

Dark Energy is basically doing work against gravity to accelerate the expansion of universe. So, for time-translational symmetry to be hold, dark energy must be converted to gravitational potential ...
-1
votes
1answer
182 views

What will happen when measuring unmeasurable object?

There is a set called Vitali Set which is not Lebesgue measurable. Analogously, there also exists a Vitali set $Y$ in $\mathbb R^3$ which is a subset of $[0,1]^3$ and $|Y\cap q|=1$ for all $q\in ...
-1
votes
1answer
124 views

How can you calculate the exact position of the Earth taking into account the gravitational attraction of Mars and the Sun?

I think there must be a formula to calculate the exact position of the Earth taking into account the gravitational attraction of Mars and the Sun. Is it possible with vectors?
-1
votes
2answers
3k views

Celestron NexStar 6 SE vs. Orion XT8 [closed]

I'm interested in purchasing a new telescope and have narrowed it down to the NexStar 6 SE vs. the Orion XT8. I'd like to be able to get into astrophotography and read that having the Go-To ...
-1
votes
3answers
105 views

Is it possible to be changed Energy Unit in future or it is strict reality in nature?

Could you pease tell me why energy unit must be $Energy=Mass . \frac{Distance^2} {Time^2}$? (I tried to write general form of Energy unit) What is the strong proof of that unit? Does it just depend ...
-1
votes
2answers
142 views

Energy required to reach 1 wavelength [closed]

I was curious if there was a forumla to find the energy required to reach 1 wavelength in a given substance. (or a vacumn if that's too hard). I am also wondering if this number can tell us anything ...
-1
votes
3answers
169 views

Earth's stationary iron core

Why is the earth's iron core stationary, while the liquid matal circles around it creating the magnetic shield. Don't understand how can the entire planet rotate where as the planet's center is ...
-1
votes
2answers
869 views

Does gravity spread instantly? [duplicate]

Possible Duplicate: The speed of gravity I am real noob in physics, so sorry if this question is really stupid. Today in a casual conversation I claimed that if the sun were to instantly ...
-1
votes
3answers
2k views

Is kinetic energy a scalar? [closed]

Is it correct to say that kinetic energy is a scalar?
-1
votes
1answer
54 views

Human and Ultraviolet light

As I know, ultraviolet light can be created from burning something at high temperature. So I have a question: Can a human body become a source of ultraviolet light at high temperature? If the answer ...
-1
votes
1answer
77 views

How can a fly be in the space of a roofless car, get out of the car space and get back in while the car is driving at the speed of 80mph? [closed]

I was driving in a cabriolet car at the speed of 80mph, while a fly flew in and out of the frame of the car. My question is, How can the fly leave the frame and get back in? Is it possible that it ...
-1
votes
1answer
63 views

Determining a person's sight from his speech [closed]

Suppose we meet a person wearing glasses.Can we determine whether the person is short-sighted or long-sighted? However,due to courtesy,we are not allowed to ask him to try the glasses and in general ...
-1
votes
3answers
86 views

Electric Current Power Calculations [closed]

With regards to the equations: $P=VI$ ; $P=V^2/R$ and $P=I^2R$, if you are given $P$, $V$, $I$ and $R$ for a circuit, how do you know which equation to use? Does the use of an equation have to do ...
-1
votes
1answer
170 views

Seeing inside an atom

After seeing this photograph and reading this article : The First Image Ever of a Hydrogen Atom's Orbital Structure I was really happy to come to know that orbitals have actually been seen now, but ...
-1
votes
2answers
67 views

Neutrinos travels through our bodies: do they contribute for gravitational atractive force?

Are neutrinos traveling through our bodies what really make us attracted to the Earth?
-1
votes
1answer
55 views

Which is more efficient cooling? Cooling yourself from cold water from Referigerator or Airconditioning? [closed]

Case a: You chill a glass of water in refrigerator to a certain temperature and drink it.. it lowers your body temperature by X degrees. Case b: You switch on the a/c for a certain duration.. it ...
-1
votes
1answer
383 views

Newtons Cannon ball problem [closed]

Let's I have a Newton's Cannon ball of 15 kg and want to fire so it will round the earth and back to me. My query is which law can evaluate the speed that cannon ball will revolve round the sun ...
-1
votes
3answers
4k views

High and low pressure area and raining

In the high-pressure area it is mostly likely that there is sun. In low pressure area it is mostly likely that rain will occur. Because of the law that ...
-1
votes
1answer
192 views

Perpetual motion

Does this video have a physics behind or it is fake? Where the energy comes from? It looks like a perpetual motion!
-1
votes
1answer
122 views

Hubble Constant and Planck Constant

Has there been any effort to understand Hubble's limit as a quantum phenomenon? It seems like they are suggesting the same thing.
-1
votes
1answer
1k views

Huygens Principle and principal of rectilinear propagation of light

Suppose I have an wave source and light waves are radiating from it. If I have a point source, then after a time t, with a radius of ct I will have a circular wave front.By Huygens principle each ...
-1
votes
1answer
205 views

What does the discovery of Higgs boson mean for steady state theory?

The relationship between the steady state theory and the notion of Higgs boson is not clear to me. What does the discovery of Higgs boson mean for steady state theory? Or are the two ideas purely ...
-1
votes
2answers
212 views

Need help buying binoculars online for astronomy (10x50) [closed]

After reading much online I've decided to by a 10x50 porro prism Binoculars. The one I have in mind http://www.letsbuy.com/celestron-upclose-10x50-p-34652 has BK7 prisms. The one I would like to buy ...
-1
votes
2answers
188 views

Is the Earth air-tight, and does that make plastic bags redundant?

Honestly though, is the Earth considered air-tight in the sense that its gases don't escape? I'm sure every physicist who reads this is going to tear their hairs out, but the extent of my knowledge ...
-1
votes
1answer
3k views

How light years is measured.?

How light years are measured. Once i remember the distance between earth and moon are measured by light which travels and comeback and by the delay the distance is calculated.. But how light years are ...
-1
votes
1answer
57 views

Is it possible to check from the EM waves(basically Light rays)?

Is it possible to check from the EM waves(basically Light rays), if there are any extraterrestrial objects interference/passage during its travel from the Sun? I mean, can these EMs from the Sun be ...
-1
votes
1answer
951 views

Radial Schrödinger equation

I found a problem that says: Show by direct substitution that $R_{10}$ is a solution of Schrödinger's radial equation. AFAIK Schrödinger's radial equation is ...
-1
votes
1answer
155 views

Behaviour of liquid in vaccume

Is it possible for a liquid to exist in a high quality vacuume? For example, a few Torr. If so what are the methods for doing this?

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