Hi there.
On my electromagnetism test there was the following question:
A long solenoid with radius R has N turns per unit length and carries a current I = I_0*cos(ωt)
Find the electric field inside and outside the solenoid.
I got the following solutions:
\vec{E} = \frac{\mu}{2} N...
If God exists outside of his own laws, the laws of science, then he exists outside of our reality, therefore he is not real.
Claiming that you know God does or doesn't exist makes you moronic then, right?
I got as far as Calc 2 in college, took some college physics and read lots of popular cosmology books. What if I want to get technical now? What specific math do I need to know to fast track it without learning things that are irrelevant? It's too late to go back to school now.
If topology of a manifold were invariant (or not), what specifically would topology of a patch of such manifold in neighborhood (outside) of such BH, suggest?
Hi,
Something weird happened the other week and I was wondering if anyone here could explain why. I run a pub and our cellar operates at about a steady 11°c all year round (cooler assisted). The other week we were enjoying some pleasant weather for the time of year(16/17°c) then wham! in the...
I'm just curious, for those of you undergrads/grad students and those of you who graduated, how many of your friends are/were within your same/related major? (like if you are/were a physics major, how many of your friends were non-physics/math/engineering majors?)
Hello all,
sorry if this is a trivial question, or if it's been asked before, but I'm not good with math terminology so my googling doesn't give me much info.. I'm trying to work out a problem in order to recreate some functions that are missing from the public API of Google Earth. (If this is...
Please can someone help me with this? Thanks in advance. :)
Homework Statement
'No charge is present on the inside surface of a charged hollow conductor'. In Faraday's butterfly net experiment, when the positively charged net is turned inside out, the outside is still charged. How does the...
Distance from Sun to "outside" galaxy?
Does anyone have a general figure regarding the distance from the Sun to the nearest place officially "outside" the Milky Way galaxy?
Thnaks.
If you were traveling near the speed of light on a spacecraft moving away from the Earth how you would you observe events happening on the earth, at normal speed or in slow motion?
I can't work this out because I know light is always gaining on you at C even if you are traveling close to the...
I am a physicist, a young physicist. I can't find information that agrees on how to determine the magnetic field at a distance from a solenoid.
We use a ferrite rod of 7.5" long wound with wire over 6.5" of it. The frequency it oscillates at is 73 kHz. If I know the current how can I...
Homework Statement
Immediately outside a very long cylindrical wire of radius Ri = 0.5 mm, the electric field (in air) is E = 40 kV/m,
away from the wire’s surface. Use clearly labelled diagrams, explain any principle/law used, for all parts.
a) What is the charge per unit length along the...
hi,
We see theoretical discussion of Electric field inside the charged capacitor is confined in the space between the plates and E.d = potential difference between plates. Considering the battery terminal(let us say positive terminal), wire and left plate or top plate, being in the same...
Homework Statement
A coil of 120 turns and radius of1.8 cm and resistance of 5.3 ohm is placed outside a solenoid. If the current in the solenoid is changed, what current appears in the coil while the solenoid is being changed?
Homework Equations
emf= -dflux/dt = A*dB/dt
emf=iR...
Homework Statement
How to find the conditions on the coefficients of a quadratic equation for the roots to be outside the unit circle eg bx^2 + x - 1 = 0 where b is a constant How do we find the condition(s) that b must satisfy such that the roots of the quadratic lie outside the unit circle...
ex: if the origin points are A = (0, 0)
B = (3,5)
C= (6,3)
How do we know that point (3,1) lies within or outside the triangle using mathematical formulas?
I know there is a similar topic to this somewhere in forums but i don't understand where a & b comes from.
please can anyone...
Homework Statement
Find the potential outside a thin, circular disc with charge q.
Homework Equations
Laplace's equation
DivgradU=0
The Attempt at a Solution
Since the problem implies symmetry around phi its obvious the solution doesn't depend on phi.
I separate the...
Hello all,
A friend of mine (physics major) recently told me that light exists outside of time. Is this true? Doesn't make any sense to me but I only know what popular science tells me.
Thanks
the problem is as follows: in the ground state of the harmonic oscillator what is the probabilty of finding the particle outside the classically allowed region. where the classically allowed nrg is given by E=(1/2)m*omega^2*a^2 (where a is the amplitude).
were given that...
Homework Statement
1) In the case of a bar magnet, outside it, the magnetic lines of forces start from North Pole and end on South Pole. But inside it, the lines of force start from south and end on North Pole. According to definition of direction of lines of force, it is the direction in...
I'm supposed to derive an equation that will find whether or not a point is inside or outside a shape with only the coordinates of the vertices given.
The shape is expected to be something like this:
______
|...|..._____
|...|______|...|
|......|_____
|........|
|........|...
A recording engineer works in a soundproofed room that is 45.0 dB quieter than the outside. If the sound intensity in the room is 1.30e-10 W/(m^2), what is the intensity outside?
I know this intensity formula ...
... I = (P/A) OR I = ( P / [(4)(pi)(r^2)] )
... and for dB ...
... beta = (10...
An insulation system is to be selected for a furnace wall at 1000 deg C using first a layer of mineral wool blocks (k=.091 W/m-c) followed by fiberglass boards (k=.0425 W/m-c). The outside of the insulation is exposed to an environment with h= 15 W/m^2-c and temp of 40 deg C. Claculate the...
Hi,
When we calculate electric field due to a charged spherical conductor at a point outside the conductor, by Gauss's law, it is equal to the electric field due to a point charge at the center of sphere, with net charge on the sphere. We can also calculate this electric field strength...
And some film technicians running around with cameras and sound booms. The streets surrounding were I am are blocked off. It's past midnight; these hollywood people are mentally ill. But we already knew that. :rolleyes:
I was searching for explanations regarding the ability of HIV to retain its ability to infect once outside the body. I know that the CDC states that natural concentrations of the virus will virtually be completely destroyed once the infectious fluid containing the virus has dried. However, I...
Hello,
The question goes like this:
A long solenoid has n turns per unit length and carries a current given by I=I₀sinωt. The solenoid has a circular cross section of radius R. Find the induced electric field at a radios r from the axis of the solenoid for (a) r<R (b) r>R
Well, i got...
Hi, I need to understand something:
A point charge -q is fixed at the center of a hollw spherical conductor of charge +q. Draw the electric field lines both inside and outside.
Please can you explain me why there is no electric field outside the sphere?
thank you
Hey everyone,
I have failed to show that the magnetic flux outside a cylindrical conductor is zero.
The problem goes like this:
a coaxial cable consists of a solid inner cylindrical conductor of radius a and an outer cylindrical conductor of inner and outer radius b and c. Distributed...
The theory is that sound is heard because of fluctuations in the air molecules that surround us but why is that we can hear noise coming from outside when we are in an enclosed room? Is it the case that air molecules are able to travel through the walls of an ordinary room?
The following is not intended as a definitive explanation of other dimensions, but a suggestion for other ways of looking at the idea of physical dimensions.
Supporters of string theory occasionally remark that the reason we cannot "see" other dimensions is that they must be very small...
It just started snowing outside. It feels like it was spring just yesterday and now its snowing already!:cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry: :cry...
We exist in the universe, with space and time.
Without space and time, there would be no motion.
If there is no space and time outside of the limits of the WHOLE(not just visible) universe, is it possible to have anything existent outside of the universe?
If nothing can exist outside of...
Hello everyone. I'm so close to getting this problem done but i can't get the last part right!
THe problem is the following:
Two long, charged, thin-walled, concentric cylinders have radii of 3.0 and 6.0 cm. The charge per unit length is 4.9 10- 6 C/m on the inner shell and -8.5 10-6 C/m...
I always want to talk some with my profs about things beyond the scope of the course, but I am shy, and worry they will feel I'm wasting their time.
Do you guys tend to do this very often?
Put a charge displaced from origin by unit distance on z axis. Now, if you try to find out about potential in space, you can usualy read, "the potential inside a sphere is proportional to r^l, and outside a sphere is proportional to (1/r)^(l+1)". I can't understand what sphere? Is it a sphere...
just finishin an essay on special relativity; and iv just realized to of the sources iv used contradict each other. If a rocket is traveling near the speed of light, and it is feeling space contraction, to an outside observor will the rocket appear to be contracting (and being flattened like a...
I've decided I definitely don't want to go back to school to learn physics, for various reasons (not the least of which I find it impossible to be guided by others). I'm wondering what affect my lack of formal education would have on my career prospects, as they relate to my knowledge of...
Ok so I'm currently going to the traditional straight into a university to get my BS and then grad school route and i was wondering something. I'm one of those people that, when they come upon a problem with any sort of 'system', they feel disabled because they don't know how to fix it. For...
Just wondering if I did this correct.
Find the volume of the region that lies inside the sphere x^2 + y^2 + z^2 = 2 and outside the cylinder x^2 + y^2 = 1
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Using cylindrical coordinates, and symmetry, I got:
I went up the z-axis, hitting z = 0 first, then exiting at...