What is Outside: Definition and 469 Discussions

Can spacetime have an outside? I sometimes read stuff where it is mentioned. Is it true?

Find E(r) inside and outside a uniformly charged spherical volume by superposing the electric fields produced by a collection of uniformly charged disks. a+b) Given equations, sketch of problem This is the equation in the handbook for a disk (but in the exercises the z becomes x, without loss of...

Homework Statement A long metal pipe of square cross-section is grounded on three sides, while the fourth (which is insulated from the rest) is maintained at constant potential ##V_0##. What is the electric field just outside the section opposite to ##V_0##? Homework EquationsThe Attempt at a...

Homework Statement WITHOUT using Gauss's law calculate the electric field at all points outside and inside an infinite cylinder with circular cross section of radius b and charge density ρ Hint: Use cylindrical coordinates and place the target charge on the x axis..Homework Equations E =...

Is there a such thing as being outside of our sun's gravitational influence? Please forgive my ignorance. I recall this formula But, what ought I plug into it, along with the sun's mass, such that I could say "it's far enough out there that there is not even a tug resultant from F"? Any...

Homework Statement this is actually mohr's circle formula, forget about the theory,let's focus on the mathematics part. I couldn't understand why the tan( 2 θs1) = -(σx -σy) / 2τxy ? 2θs1 is outside the triangle Homework EquationsThe Attempt at a Solution theorically, tan(180-α )= -tan( α ) ...

I need help in calculating the magnetic field outside of an iron core solenoid at different distances. I have made an electromagnet by taking a 99.99% pure iron (5cm in length and 1 mm in radius) and wrapping wire over it. I have measured it's magnetic field at the end and cannot find an...

Hi, Can people please help me with this both qualitatively and quantitatively... 1) If I have a long straight wire carrying a DC current, what field(s) should I expect outside of it? 2)a) If, as an example, I had a stream of charge particles (say electrons), moving perpendicular across the...

A friend and I have been debating a topic for the last few days and I would really like a more informed opinion on the discussion. My friend says that IF you could, some how, see the universe from the outside and it appears that the universe is a finite flat, spherical shape, or other shape...

Hi there, We can't use Infrared rays outside for data communication of our home as sun light also contain infrared rays which possible will interfere with it.That's what i read in Data communication book. My Question is , Does sun rays also contain radio wave, microwave ? if yes, then why can't...

How come the magnetic field outside a solenoid is practically zero? I've read reasons along the lines of: -The magnetic field cancels out on the outside. Of course the net force cancels out, but what if you have an object placed on just one spot? The force on that object clearly is not 0...

Homework Statement A marble rolls from the top of a big sphere. What is the angle θ when the marble is about to leave the sphere? Assume a zero speed at the top. Homework Equations The question came from the chapter Mechanics - circular motion. The Attempt at a Solution I can't conceive what...

I need a way to generate cool air outside when temperatures are 90s and above. Basically what I am thinking of doing is essentially like positioning a fan right beside a bowl of ice cubes. Only in my case, instead of using ice cubes, an electrically powered cooling device that can slightly...

My house has basement and one floor. When outside is 7 to 10 degrees warmer than the day before, bedrooms, living room always get colder. where did the cold air come from? I am assuming cold comes from basement. I know cold air always is at bottom...heavier than warm air near the...

I'm trying to deal with the supremum concept in a specific situation, but I think I'm getting the concept wrong. A step of a proof I'm going through states: P\ [\sup\limits_{x}\ |f(x)\ -\ f'(x)|\ >\ y\ |\ z]\ \ \leq\ \ \sum_{i=1}^M\ P\ [\ |f(x)\ -\ f'(x)|\ >\ y\ |\ z]\ \ \leq\ \ M\times\...

My questions is about the conversion of a range of wavelengths in Hz, such as for an optical filter, in a medium different from air. Since the refractive index n is higher than 1, (let's say n=1.5) and than the value of c is almost 2x108 m/s, also the equation in the link below has to be...

I refer to the time coordinate of an outside observer (ideally hoovering over the BH at large constant distance). Can (s)he actually see something falling into the hole within finite time, that means actually disappearing and making the Event horizon larger? If no, all the merging of black...

Hello If we have a gaussian surface that is placed in a uniform electric field E and encloses 0 charge, what would the E-field at the gaussian surface be? I have assumed the gaussian surface to be cubic surface, and then I have found from Gauss's law that the electric field is zero at the...

Why is the electric field just outside a conductor twice the field produced by a uniform sheet of charge? My textbook's explanation is that you can imagine that near a point P, the charge at the surface of a conductor looks like a small uniformly charged disk centered at P, giving an electric...

Really quick question, what exactly does the fan of the outside part of my split ac do? That fan seems to just make wind for no clear reason. I'm curious to know what it actually does.

Homework Statement I found solution to problem 257 from "300 Creative Physics problems" hard to understand. In that problem we have very long solenoid with coil wounded in one layer. Data such as: density of turns, magnetic field at distance of 5 cm form the axis of solenoid and diameter (1 cm)...

In short, I have great grades and research experience in physics, but my second major, music, brings my GPA way down. Also, I'm a 3rd year undergrad, and I'm wondering whether this will be a significant problem when I apply to schools next year. This is a problem that I haven't seen often or...

Wondering if somebody could help me. I'm in the 3rd year of a 4 year MPhys course and at the point where I am actively applying for placements/internships etc and thinking about what to do after university. I love physics don't get me wrong, but really don't fancy staying at uni for another...

Is it similar to the Newton's cradle principle? This is fluid mechanics/control volumes. There is fluid flowing through a duct and it's being analysed using a control volume surrounding the duct For example in this question the atmospheric pressure is having an affect on the fluid within the...

Homework Statement How do I get the equivilent circuit in this scenario? The battery is not directly connected within the circuit. I know how to find the equivilent resistance in situations where the battery is "inside" the circuit but I am having a little trouble with this one. The voltage...

Homework Statement 1. We are considering a step junction at equilibrium(no external voltage applied). 2. The potential variation is shown as negative potential at P region(which is shown as constant) and increasing through the transient region to become positive in the n region. Homework...

Homework Statement 1. We are considering a step junction at equilibrium(no external voltage applied). 2. The potential variation is shown as negative potential at P region(which is shown as constant) and increasing through the transient region to become positive in the n region. Homework...

I'm an average joe here, trying to figure something out. Let's say I have a tube and a disk that travels from top to bottom pushing air kinda like a pump. Both tube ends are open so as air is pushed out of the bottom end, more air flows in through the top. Here is my question: Does pushing air...

Homework Statement Find the potential outside a charged metal sphere (charge Q, radius R) placed in an otherwise uniform electric field E0. Explain clearly where you are setting the zero of potential. 2. The attempt at a solution So for this problem I figured I could exploit superposition and...

Homework Statement A point charge of +5.00 μC is located on the x-axis at x= 5.00 m , next to a spherical surface of radius x= 4.00 m centered at the origin. [/B] According to Gauss's law, the net flux through the sphere is zero because it contains no charge. Yet the field due to the external...

Can anyone way in on the correct Formulas of a Solenoid Magnetic B-field at Ending, Middle and Outside? I have the following so far but some of them seem to contradict one another . Photo #1: Photo #2: Photo #3: Photo #4: Photo #5: Photo #6:

why do electric field is zero out side of depletion region?

Hi, I'm trying to write the current density for such circular loop in spherical coordinates. For a circular loop of radius a that lies in the XY plane at the origin, the current density it's simply: \mathbf{J}= \frac{I}{2\pi\sin\theta}\delta(\theta-\frac{\pi}{2})\frac{\delta(r-a)}{a}\hat{\phi}...

My trig. is so-so (I honestly hated it) and just curious how much it's used and needed in other maths? Thanks.

Homework Statement Hi everyone. I m just studying capacitors but I have problems with gauss law. In one exercise it says that we have a sphere(cavity) of radius r, with a charge q placed inside the sphere of it. Wie have to find the electric field inside and outside sphere. The solution says...

Homework Statement I am preparing a report on black holes and I recently learned about a phenomenon I was previously unaware of: the photon sphere of a black hole. While reading an article on said occurrence (I have now confirmed this on multiple sources) the photon sphere which is the minimum...

(Title should read "for" PhD Physicists... I can't type today) From Science Daily: The one graint of salt to take this report with is the fact that 10-15 years before 2011, was well into the dotcom boom, where physics PhDs were aggressively recruited for their number crunching skills. It...

The field outside a coil is given by I notice permeability of vacuum in the expression, and this makes sense since we are evaluating the field in space. Is there any effect to the coil having a ferrite core? Looks like there should not be (again the field is evaluated in space). However...

Hi, hope this is not too dumb: Is it possible to create paint or clothes whose color is outside of the visible range (of course, we need to then store them in receptacles within the visible range )? Is a substance/object's "natural color" (I guess this is the color in which it either appears in...

Homework Statement A thin metallic spherical shell contains a charge Q over it. point charge +q is placed in side the shell at point T separated from the centre by a distance a. Another point charge q1 is placed outside the shell at a distance b from the centre find the electric field at the...

Homework Statement I'm asked to calculate the propability of finding a particle outside the classical limit for a quantum harmonic oscillator in it's ground state Homework Equations Ψ0(x) = a*emωx2/2hbar When a = (mω/πhbar)1/4 The ground state energy E0 =hbar*ω2/2 The Attempt at a Solution I...

Homework Statement For the equation ∇ x E = -∂B/∂t I took the curl of both sides to get ∇ x (∇ x E) = ∇ x -∂B/∂t I feel like it'd be very wrong to pull out the time derivative. Am I correct?

Imagine a surface charge ##\sigma##. The boundary condition on ##E## is ##E_{above}-E_{below}=\frac{\sigma}{\epsilon_0}\hat{n}##, where ##\hat{n}## points outwards perpendicularly to the surface. Because the field inside a conductor is zero, it requires that the field immediately outside is...

Homework Statement Consider a sphere of radius ##R##, with a charge density ##\rho(r)=\frac{\alpha} {r^2},## with ##\alpha## a constant. Use Gauss' law to calculate the electric field outside the sphere at a distance ##r## from the sphere's centre (ie. ##(r > R)## and inside the sphere (ie...

There is only one planet (Earth)have life in the universe.But this is invented by human; the son of Earth! Is any other life live away from the solarsystem? I don’t know!…..oureyes&ears reach not so much. We are the most advanced biota among others in the earth. And we take oxygen as the life...

Hey guys, I'm new to the forum and I got to say I'm glad I found it because boy do I have questions. Basically, I'm a sophomore in college, I just switched my major from finance to physics and I'm stoked. I just finished the pre-req to intro physics which was Calculus so this upcoming semester...

Homework Statement Turns of wire would around a toroidal core, carrying a sinusoidal alternating current i(t), represent a toroidal coil in my case. My question is, does magnetic force affect a non-moving charge outside of toroidal core and is there a magnetic field outside of toroidal core...

Considering that the electric field exist outside a battery in a wire,shouldnt the potential drop while we move along the wire even if there is no resistor(E=grad(V))?Because when i see diagrams of potential along the wire,they all show a constant potential along the wire until it reaches a...

Correct me if I'm wrong,but a battery's electric field is like an electric field of a capacitor consisting of two plates.But we know that the electric field outside the two plates is zero.So why does an electric field form outside the battery and into the circuit?

Homework Statement A 91-kg astronaut floats outside a 3,131 kg spacecraft . She's initially stationary with respect to the spacecraft . Then she pushes against the spacecraft , and moves away at 0.195 m/s to the left. Find the SPEED of the recoiling spacecraft . Homework Equations Force =...