Conductor Definition and 821 Threads

Homework Statement A point charge ##q = −5.0\times 10^{−12} C## is placed at the center of a spherical conducting shell of inner radius 3.5 cm and outer radius 4.0 cm. The electric field just above the surface of the conductor is directed radially outward and has magnitude 8.0 N/C. (a) What is...

I'm confused as to how this expression E= (δ/εo) can't be used to calculate the electric field of a perfectly flat part of a surface even farther from just above the surface.If you just extend the same cylindrical Gaussian surface used for this proof, wouldn't the field stay the same no matter...

Homework Statement A Sheet of conductor of thickness t and parallel faces of cross-sectional area >=A is inserted between the plates of the capacitor of a parallel plate conductor. Show that the capacitance increased by ΔC= ε0tA/d(d-t) Homework Equations σ,ε0,Δ The Attempt at a Solution...

Homework Statement Two identical conductors are brought into contact. Initially one conductor has a charge of +30 x10^(-6) C, what is the charge of each conductor afterward? Does it matter how the contact is made? Homework EquationsThe Attempt at a Solution Well since they are conductors...

Homework Statement Hi guys, I'm currently writing an extended essay in Physics looking at the effect of percentage composition of Sn has on the electrical resistivity of SnPb Solder. I've noticed that Sn is listed as being a better conductor than Pb, despite trends of periodicity and have been...

Situation is this, consider a conductor moves perpendicular to the direction of magnetic field. But magnetic field is not uniform through out the conductor movement( but magnet is stationary and flux lines are in same direction and magic field doesn't change with time but changes with space...

Please explain me the following answer Q)When a current is passed through a conductor, will it be charged? A)Charge carriers participating in conduction in a conductor are not excess charge carriers. The number of free charge carriers is equal to the number of opposite charge on the nearly...

Homework Statement Consider a conductor loop which rotates about the y-axis with angular velocity w. The positive y-axis is directed into the paper, the x-axis to the right and the z-axis upwards. There is an inhomogeneous magnetic field along the positive x-axis. Calculate the magnetic flux...

Ques : If a neutral metal sphere placed on an insulating stand is touched by a charged plastic rod , does the metal sphere acquire any charge ? I think that by simply touching the sphere by insulating rod , the metal should not acquire any charge as the charges on the rod are immobile unlike a...

Homework Statement A + q = 5 pC charge is uniformly distributed on a non-conducting sphere of radius a= 5 cm , which is placed in the center of a spherical conducting shell of inner radius b = 10 cm and outer radius c = 12 cm. The outer conducting shell is charged with a -q charge. Determine...

It can be mathematically shown by Gauss's law that it is true but physically how? In case of a symmetrical conductor(Eg Sphere,Cyllinder) there are charges uniformly distributed and field of one charge cancels out the opposite charge's field! But which are not symmetrical, for them what makes...

Homework Statement Homework EquationsThe Attempt at a Solution i have done the first two parts but the third part confuses me i am assuming the current is flowing in the z direction then current is parallel to the magnetic field then why would there be a force acting on it ?[/B]

In this image charge q is enclosed within an arbitrary shaped conductor. I'm asked to find what if the Electric field in regions 1,2,3,4 are uniform and if the surface charge densities on the interior wall of the arbitrary shaped conductor and the hollow sphere conductor are uniform. My...

Why is a sea of electrons present in a conductor? I read some where that they absorb a energy at normal temperatures and use it to get free electrons , but then why do they absorb energy while insulators don't??

Homework Statement Homework EquationsThe Attempt at a Solution [/B] This is a quite a fundamental question in electrostatics and I felt pretty embarrassed getting it wrong .I thought correct option was d) . Could someone help me understand how conductor could acquire charge as charges...

potential energy is the work done by an external force in taking a body from a point to another against a force. on the surface of a conductor the electrostatic charges arrange themselves in such a way that the net electric field is always zero. so if there isn't any force to act against why...

As shown in figure, we know that at the sharp end E field is strong, and at the other end field is weak. Inside the conductor E=0. that means V=constant. on its surface and throughout the conductor. if we move unit positive charge from B to A or P to Q (as shown in fig.) then different amount...

Hello, and thanks in advance for taking a look at my question. Generally, I am trying to make a railgun force model. Since railguns depend on the magnetic field created around the rails (and the resulting Lorentz force) I need to model the magnetic field created by the current that flows...

There's been a discussion going on since this following thread: Range of frequency of electromagnetic wave how electric current flow through a conductor. I need a proper clarity, does the electrons literally displace and flow or just the disturbance/energy travel through conductor making...

Some things I did not get are, 1): In the third para, it is said that potential approaches ##\infty## at ##Q##, why ? 2): In last para, The z component of field by ##Q## is said to be ##-Qh/(r^2 + h^2)^{3/2}##, Why ? should not it be ##+Q## not ##-Q## has the charge itself is positive. 3): I...

We know that there exists no electric field inside a conductor. But while calculating drift velocity of electrons inside an electric conductor, why do we consider the electrons are present inside the charged conductor?

Homework Statement Consider a plane monochromatic wave incident on a flat conducting surface. The incidence angle is ##θ##. The wave is polarized perpendicular to the plane of incidence. Find the radiation pressure (time-averaged force per unit area) exerted on the surface. Homework Equations...

A current loop has a wire starting at its center. The wire terminates at the inside of the loop. The loop and wire have 150 and 15 ohms of resistance respectively. Both have 4 volts of potential across them. Looking at this I understand the the wire will experience a lorentz force because the...

Hello, Please consider this diagram: From the diagram, we can see there are two forces. One: The Lorentz Force (qvB). Using the RHR, we can see that there is a force pushing north (up) to cause the separation of charges in the sliding conductor to establish the current in the loop. Two...

I would like to know why electric field of EM waves changes it's direction to opposite when hitting a conductor surface. I know that electric field inside a conductor is zero but I am not able to connect these two situations.

I read in a book that during normal working condition (balanced system) the current through a neutral conductor is zero i.e., Ia+Ib+Ic =0 where Ia, Ib, Ic are phase current of three different phases a, b, c. How is that possible? I mean if you look at mathematical result of the phases they are...

I read on physics.stackexchange that using Gauss Law we can prove that the electric field strength increases as the radius increases inside a metallic conductor. Later on the same website, I encountered a contradicting statement that claimed that inside a conductor, the charges aren't free to...

So i have learned about the ability of Faraday Cage for blocking an external electric field. But is the thickness of the conductor effect the ability? Is there any limit of its thickness so that the cage won't be able to block external electric field anymore? I have read and searched about this...

Homework Statement Homework Equations I = nqVA J = E/ρ J = I/A The Attempt at a Solution The underlying assumption was that current was constant across all 3 bits of the conductor, and thus answer is b. The concept I can't grasp is this: Why is current constant? Shouldn't a smaller A mean...

An electric dipole p with arbitrary direction and is at distance a from plane infinite conductor at z=0. Using the image of the dipole ##p=(2pcos\theta \hat{z}+psin\theta \hat{x}## ##p'=(2p'cos\theta \hat{z}-p'sin\theta \hat{x}## Using the...

I'm no physicist, but I found this material to be interesting. Samarium Hexaboride is a crystal that exhibits conductive properties at room temperature and insulating properties when cooled to below minus 223 degrees Celsius. A layman's article...

Homework Statement A long (infinite) wire (cylindrical conductor of radius R, whose axis coincides with the z axis carries a uniformly distributed current I in the +z direction. A cylindrical hole is drilled out of the conductor, parallel to the z axis, (see figure above for geometry). The...

I just read in my textbook that it is impossible to harness electricity from the induced emf if the velocity of a conductor is parallel to its straight length. Let me elucidate further: a magnetic field goes into the page and a straight conductor is moved straight down or up (perpendicular to...

Homework Statement [/B]Homework Equations V= kq/r.[/B]The Attempt at a Solution For 8-8, I do not really know how to approach it. For 8-14 , I think that q2=-q1 and q3=q1+q2. I can now use V=kq/r and then find the equations for r>R3 , r=R3 , R2<r<R3 , r=R2 and R1<r<R2 and then graph...

Hi everybody, I have an oscillating circuit that consist of a charged capacitor and two conductors connected that can be seen as the inductance. When I short the conductors at their ends an oscillation can be seen on the oscilloscope. When I put an iron tube around each of the wires the damping...

Homework Statement An infinitely long, hollow, conducting cylinder has a inner radius a and outer radius b and carries a linear charge density λ along its length. What is the electric field everywhere? Homework Equations ∫E⋅dA = Qenc/∈ Variables ∈ = permittivity constant a = inner radius b =...

Homework Statement A grounded Z-axis symmetric closed conductor has a single point charge at the origin within it, inducing negative charge onto its inner surface. Given the induced charge density from the unit point charge, find the surface charge induced instead by a unit dipole at the...

Homework Statement A cylindrical conductor of radius ##a## has a hole of radius ##b## and there is a current ##i## uniformly spread inside the conductor. Calculate the magnetic energy of the conductor. Homework Equations $$U_{m}=\int_{Volume} \frac{B^2}{2 \mu_0} dV$$ The Attempt at a...

Could a good conductor, like some metal, be heated past the temperature of the heat that's heating it. Like if I use a 100 degree flame and hold it for hours on some piece of metal, could the metal go above 100 degrees? And I'm not talking about special cases. I mean does this generally happen?

This question comes from the equation E = vB (moving conductor in a magnetic field -- E = electric intensity, v= speed of the conductor's movement, and B = magnetic field strength). Say B is constant, so the only thing we have to rely on to vary the electric intensity in the conductor is its...

Hi, While studying the coaxial cable, i noticed that the magnetic field of the inner conductor can pass through the hollow conductor (can be calculated in the region 3). However, the boundary condition of the magnetic field at the surface (between dielectric and perfect conductor) of a perfect...

Homework Statement Given the figure below[/B] I need to calculate the total magnetic force on the semicircle section of the conductor. Current is I, Radius is R, and the Magnetic Field is B. Homework Equations d\vec{F} = Id\vec{l} \times \vec{B}[/B] The Attempt at a Solution [/B] dl is...

Homework Statement [/B] Two long, coaxial metal cylinders are separated by a material of conductivity sigma and dielectric constant epsilon. The radius of the inner cylinder is a, the radius of outer cylinder is b, and the length of both is L. Suppose that the inner conductor is held at a...

I wonder if my thought experiment in proving the finite speed of field lines is valid. Say a spherical conductor has a cavity with positive charge Q inside as shown. say that the beginning of the universe starts at time 0, where there is the charge Q in the cavity and that the conductor is not...

Hi. If an electrically neutral, conducting rod is brought close to a (say negatively) charged object with one end, charges will separate due to electrostatic induction roughly as follows: Let's now connect the rod to the (far-away) ground with a long cable. Does it make a difference whether...

I know there is a lot of answers out there, but so far none really answered my question. Say I have this radioactive conductor sphere that has a negative charge. Of course, all the negative charges will be spread evenly on the surface and there SHOULD be 0 electric field inside the conductor...

Hi. I learned that in an ideal conductor in a circuit, the voltage drop is zero. But how does this agree with the basic definition of voltage $$U_{AB}=\int_A^B \vec{E}\cdot d\vec{s}\enspace ?$$ The electric field inside a conductor only vanishes in static conditions, but in an electric circuit...

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...

Hello ! 1. Homework Statement i study for my exams. here is my current problem: a non-specific conductor is connected to an ideal battery (surrounding temperature: 20°C) and reaches a temperature of 24 °C . after cut in half it is again connected to the battery. what temperature does it reach...

Homework Statement What is the EMF generated in a straight conductor of length L placed in a time varying magnetic field B as shown in the below figure.. Homework EquationsThe Attempt at a Solution Time varying magnetic field is B.cosωt, EMF = (d/dx)(B.L.cosωt) = -B.L.ω.cosωt I don't know...