What is Potential: Definition and 1000 Discussions
Potential generally refers to a currently unrealized ability. The term is used in a wide variety of fields, from physics to the social sciences to indicate things that are in a state where they are able to change in ways ranging from the simple release of energy by objects to the realization of abilities in people. The philosopher Aristotle incorporated this concept into his theory of potentiality and actuality, a pair of closely connected principles which he used to analyze motion, causality, ethics, and physiology in his aPhysics, Metaphysics, Nicomachean Ethics and De Anima, which is about the human psyche. That which is potential can theoretically be made actual by taking the right action; for example, a boulder on the edge of a cliff has potential to fall that could be actualized by pushing it over the edge. Several languages have a potential mood, a grammatical construction that indicates that something is potential. These include Finnish, Japanese, and Sanskrit.In physics, a potential may refer to the scalar potential or to the vector potential. In either case, it is a field defined in space, from which many important physical properties may be derived. Leading examples are the gravitational potential and the electric potential, from which the motion of gravitating or electrically charged bodies may be obtained. Specific forces have associated potentials, including the Coulomb potential, the van der Waals potential, the Lennard-Jones potential and the Yukawa potential. In electrochemistry there are Galvani potential, Volta potential, electrode potential, and standard electrode potential. In the
thermodynamics, the term potential often refers to thermodynamic potential.
Homework Statement
[a) Show that chemical potential in intrinsic semiconductor at T = 0 lies exactly in the middle of the energy gap. At what temperature is the chemical potential equal ##(3/4)(E_c + E_v)##, where ##E_c## and ##E_v## are energies od the bottom of the conduction band and of the...
Homework Statement
When a point charge is positioned at the origin = 0 in an isotropic
material, a separation of charge occurs around it, the Coulomb field of the
point charge is screened, and the electrostatic potential takes the form
\phi(r) = \frac{A}{r} \exp\left( -\frac{r}{\lambda}...
Do exist examples of attraction forces with such a type potential
##V(\boldsymbol r)\sim-\frac{1}{|\boldsymbol r|^2}, \quad |\boldsymbol r|\to 0##
in physics ?
Hi All,
The Potential Energy for two chemically bonding atoms is defined by ,U=1/2(k*q1*q2)/r
So it means that when the atoms approach each other then, their Potential Energy will increase.
Where am I doing wrong?
I will be thankful for help!
I have read that postdocs are extremely hard to come by in Astrophysics, and is likely a dead end at the end of the PHD and that Condensed Matter is less competitive in academia. Would a Condensed Matter PhD also provide more opportunities in UK science industry - in particular the life sciences...
Lets suppose we put a point particle with a mass m here on earth. No energy was used to put it there. It makes sense it will go down, but where does gravity gets the energy to pull the particle? from the earth/particle mass?
Homework Statement
Hence calculate the expectation value and uncertainty of the mutual potential energy of the electron and proton for a hydrogen atom in this state.
This is the Coulomb model, and that is the question. I just need to know if 'mutual potential energy' means the effective...
1.Data: We have an truncated cone with a volumentric charge density ρ, and it's uniform. The image show the truncated cone and show some info of the radios.
2. Question. We need to calculate the potential on the vertical axis.
note: adding an image of the problem but it's in spanish, hope...
HiI was reading about capacitors and potential energy. But the equation seems counter to how i thought.
For potential energy you have:
U = Q^2 / 2C
or
U = CV^2 / 2
But doesn't this suggest you lose potential energy the more capacitance you have? Since in the first equation as C increases U...
For this problem at t=0
Ψ(x,0)=Ψ1-Ψ3
Where Ψ1 and Ψ3are the normalised eigenstates corresponding to energy level 1 and 3 of the infinite square well potential.
Now for it's time evolution it will be Ψ1exp(-iE1t/ħ)- Ψ3exp(-iE3t/ħ)
And taking the time given in the question the time part of the...
Homework Statement
Homework Equations
For this question my ans. is coming option (3) since the time part of the wave comes out to be same for both the energy states which is (-1)^(-1/8) and (-1)^(-9/8) respectively (using exp(-iEt/ħ)).
But the correct option is given option (4).
Am I right...
My question is given an orthonormal basis having the basis elements Ψ's ,matrix representation of an operator A will be [ΨiIAIΨj] where i denotes the corresponding row and j the corresponding coloumn.
Similarly if given two dimensional harmonic oscillator potential operator .5kx2+.5ky2 where x...
Homework Statement
Suppose the potential in a problem of one degree of freedom is linearly dependent upon time such that
$$H = \frac{p^2}{2m} - mAtx $$ where A is a constant. Solve the dynamical problem by means of Hamilton's principal function under the initial conditions t = 0, x = 0, ##p =...
Let's say the solution on the left hand side is a sinkx + b coskx = 0
We get one solution for each E if we omitted a and another solution if we omitted b. However, how to conclude that they are all the solutions? Will there be any solution of the 5 coefficients such that a and b are both not...
Homework Statement
My main conceptual issue here surrounds positives and negatives as they apply to electric potential difference. I will post two questions that illustrate my confusion, if that's ok.
1) The electrons in an old TV picture tube are accelerated through a potential difference of...
Homework Statement
I'm trying to do a problem two ways, and things aren't consistent, finding the electric potential difference in a linearly varying field.
The electric potential difference between two points is often summarized in texts as ΔV = Vf - Vi = - ∫ E⋅ds where the lower bound of...
Homework Statement
A toy car is held at rest against a compressed spring, as shown in the figure. When released, the car slides across the room. Let x=0 be the initial position of the car. Assume that friction is negligible.
Sketch a graph of the car's kinetic energy from the moment it is...
Homework Statement
A 1.00 kg ball is thrown directly upward with an initial speed of 16.0 m/s.
A graph of the ball's gravitational potential energy vs. height, Ug(h), for an arbitrary initial velocity is given in Part A. The zero point of gravitational potential energy is located at the height...
1. The problem statement
Two charges of 3μC and -2μC are placed 2cm apart. At what point along their connecting line is electric potential zero?
Homework Equations
Electric potential superposition Φ=Φ1-Φ2 since q2 is negative
Φ=kq/r^2
The Attempt at a Solution
Let’s say the charges are on the...
Consider the classical scenario a stone falling in the Earth gravitational field.
Classically we attach a Potential Energy to the stone and using the law of conservation of (mechanical) energy we are able to evaluate the dynamic of the falling stone.
This model assume a stone in a "external"...
Assuming generlized variables, q, we have a Lagrangian in mechanics as the kinetic energy, K, minus potential energy, U, with a dependency form such that
L(q,dq/dt) = K(q, dq/dt) - U(q)
Can someone provide examples of Lagrangians in other disciplines?
So the work done when charging up a capacitor is ##dW=VdQ##
However, when we add a charge ##dQ## to the capacitor, ##V## also changes accordingly, so I was wondering why the work done wasn't written as ##dW=VdQ+QdV## (one that also takes into account t he change in ##V##).
Thanks in advance.
There is no absolute electric potential.
Is it due to classical ignorance (because we don't know the static fields, capacitive coupling, etc. of the surrounding environment) or is it due to quantum ignorance (the potential can fluctuate to any value due to HUP)? My question is valid because...
Homework Statement
Consider a particle of mass m moving in a one-dimensional double well potential
$$V(x) = -g\delta(x-a)-g\delta(x+a), g > 0$$
This is an attractive potential with ##\delta##-function dips at x=##\pm a##.
In the limit of large ##\lambda##, find a approximate formula for the...
Homework Statement
A 3.20kg rubber ball drops from a height of 4.80m to the ground a bounces back to a height of 2.70m
a) how much potential energy does the ball lose on the trip down?
b) how much energy does the ball regain on the trip back up?
c) what is the net loss of potential energy...
Homework Statement
We have the cross section of a metal pipe that has been split into four sections. Three of the sections have a constant electric potential, Vo. The fourth section is grounded so electric potential is zero. We are looking for electric potential inside and outside of the pipe...
Homework Statement
Four identical cells each having emf E and internal resistance r are connected in series to form a loop abcd as shown in figure (picture 1). Find potential difference across ab and ac.
2. Homework Equations
V=IR
equations for combination of cells and resistances
The...
Homework Statement
Does a point in a wire having higher potential necessarily mean that it has a higher electric field?
For example consider the cases of question 27 and 31 in the picture attached below.
Homework Equations
E=V/L
The Attempt at a Solution
The potential at a and b is the same...
I’ve seen the uncertainty principle used to calculate the ground state energy for things like hydrogen and the harmonic oscillator, but can this be done for the Yukawa potential where you have an exponential?
Homework Statement
The change in gravitational potential energy of a mass m as it moves from the surface to a height h above the surface of a planet of mass M and radius R is given by:
ΔPE= GMmh/R(R+h)
a) show that when h is very small compared to R , this approximates to the more familiar...
I have been reading the book "Nanostructures and Nanomaterials" by G. Cao and Y. Yang, and was intrigued by the following passage in page 33:
"Assuming the vapor of solid phase obeys the ideal gas law, for the flat surface one can easily arrive at:
μv − μ∞ = −kTlnP∞, where μv is the chemical...
Homework Statement
I have a force ##\vec{F} = a_x\vec{i}+2a_y\vec{j}+3a_z\vec{k}##. Find the potential
Homework EquationsThe Attempt at a Solution
Lets suppose
And we know that ##\vec {F} = ∇U##
In this case I said that
##U_x=-\int F_xdx##
##U_y=-\int F_ydy##
##U_z=-\int F_zdz##
and then I...
Homework Statement
A particle of mass m in one dimension has a potential:
$$V(x) =
\begin{cases}
V_0 & x > 0 \\
0 & x \leq 0
\end{cases}
$$
Find ##\psi(x)## for energies ##0 < E < V_0##, with parameters
$$k^2 = \frac{2mE}{\hbar^2}$$
and
$$\kappa^2 = \frac{2m(V_0 - E)}{\hbar^2}$$...
[Note from mentor: this was originally posted in a non-homework forum, so it does not use the homework template.]
There is a general relation between the work U required to assemble a charge distribution ρ and the potential φ(r) of that distribution:
U = 1/2 ∫ ρ...
So I have been wondering:
The potential for a point charge at the origin, is described as:
(Using the reference point at infinity): V=1/(4πε) * q/r
My question is, what happens to this Potential the closer we are to the point charge, and so the closer we would get, the Potential seems to go...
Homework Statement
True statements about Jupiter as it moves in its elliptical orbit around the Sun include which o the following?
I. It has its greatest speed when closest to the Sun.
II. It has its greatest potential energy when farthest from the Sun.
III. The magnitude of its...
The electric potential can be defined as
V = - ∫C E⋅dl
where we are taking the line integral along C from some convenient reference point O, where we have set V = 0, to the point r we are trying to find the potential at. Of course, C can be any curve, but it's usually the most convenient to...
Hello! I am going to talk here about a real scalar field for simplicity. If we have a Higgs-like potential for a real scalar field, the graph of the potential looks like a section of a "Mexican hat", with a bump at 0 and two absolute minima at, say, ##\pm a##. This is the plot I see in any book...
Homework Statement
My question is more about understanding the task itself, not about calculation.
I am supposed to use the poisson equation, to derive the potential inside a semiconductor for a barrier with potential height ##\phi_B## and a donator doping with ##N1 > N2##. Then I should use...
So in my textbook (Introduction to Electrodynamics by Griffiths) it said that inside a conductor, the electric field E would have to zero, since if it wasn't the free charges would move accordingly and create a electric field that cancels the original field. But in a question that soon followed...
Hi,
I'm studying MOSCAP at university and there are 3 regions based on Vg.
Accumulation
Depletion
Inversion
For P substrate the surface potential increases as I increase the gate voltage (positive). The books say that at Vg = threshold voltage the surface potential is maximum. But why does it...
Homework Statement
Which graphy represents the potential energy of the block as a function of time?
Homework Equations
PE=mgh
The Attempt at a Solution
First, the potential energy is zero until it reache the top of the incline where the potential energy is maximum. Moving down, the potential...
Hi at all!
This is not a homework or simila, so I'm sorry if I post my question in a wrong section, but I do not know where to post it.
In the nuclear case, the Wood-Saxon potential is the main empirical potential used to describe the nucleus.
What would be the analogue in the atomic case?
The...
Hello,
I haven't been able to find the answer to this anywhere.
When calculating the energy gained by a particle that is accelerated across the gap of two cavities (e.g. Dees in a cyclotron, or charged cylindrical cavities of a linear accelerator), does one need to take into account the size of...
Homework Statement
This problem is belonging to a book, which is material for Vietnamese students who will take part in IPhO (International Physics Olympiad). Since this problem is written in Vietnamese, I will try my best to translate it to English:
A vacuum diode consists of two parallel...
Homework Statement
Show that the variation of gravity with height can be accounted for approximately by the following potential function
V = mgz(1+z/re)
in which re is the radius of the Earth. find the force given by the above potential function.
Homework Equations
V = GM/r
The Attempt at a...