Hi, I was wondering about a simple example.take a coil wound on a solenoid, one side of the solenoid core is permanently attached to a permanent magnet S pole, the other end of the solenoid core is not attached to any magnet.
Now I take another magnet turn it with the N pole facing the solenoid...
Homework Statement
A direct current i=10 A flows in a long straight round conductor.Find the magnetic flux through half of the wire's cross section per one metre of it's length.
Homework EquationsThe Attempt at a Solution
I have spent quite a while thinking on this problem but I can't think of...
If a conductor carrying current has magnetic flux around it,why not a carrier wave that carries current in case of wireless power transfer has a magnetic flux around it?
I am fixed to find out the reason what makes the charges get separated in conductor causing an emf leading to induced current. A very good reason exists for motional emf. It can be explained with the help of F=qvBsinΘ.
Let's say I place two different size conducting loops inside of a uniform magnetic field. For the sake of the diagram I have the loops share a point, but just treat them as though they are not touching.
Then I decrease the value of the magnetic field very quickly.
\frac{dB}{dt} =...
Suppose that a ferrite bead is put around a cable where a constant current I flows, just like in this image.
The coordinate system has the z axis along the cable. Let's evaluate the current through the (x,y) plane: according to the Ampère's law, the only magnetic field component generated by...
The book I am working through is beginning to dive into induced currents and Lenz's Law.
When a conductor is moving perpendicular to a magnetic field, the charge carriers inside will experience a magnetic force; This causes the charges to move. Eventually, the electric field from the charge...
Magnetic fields are less harmful than electric field and also a lot safer than being exposed to electromagnetic radiation. If data transfer is possible through magnetic flux then cancers and all those kind of diseases can be avoided. So, the question again is can a magnetic flux(movement of...
If we have a conducting loop, and a magnet (say North pole first) is pushed into it; that induces and emf and hence a current in the coil due to the changing magnetic flux, right? According to Lenz' law, the direction of the current is such that it opposes the change. So from the side the magnet...
I am looking to find the magnetic flux of a cylindrical magnet as it passes through a coil. I am aware of the complexity of magnetism, however, i am only looking for a conservative approximation of the magnetic flux. I found the formula ΦB = B · A, but is my understanding that the magnetic...
Flux is defined as (Area Perpendicular to field) x (magnetic field). If a magnet is traveling through a coil of wires. How do you figure out the area perp to the field?
Imagine a ferromagnetic medium shaped as a cylinder (a ferromagnetic fiber) with a magnetic relative permeability of μr, tilted with an angle a, as shown in the picture.
I would like to prove analytically that the sum of the inductances measured along the x-axis (angle is a) and y-axis...
i can not seem to figure out how is the magnetic flux is changing and thus the current is induced , "A "is constant (same disk is spinning ) and "B" is constant and does not change , so how is the current induced ?
and more specifically how is the change of magnetic flux is happening ?
thanks...
There is a conservation law for superconductors " the flux through a superconducting ring cannot change". This can be shown using Faraday's law: -
E.M.F=-d/dt (BA) where B is the measured magnetic field passing through the ring and A is the area enclosed by the ring
therefore for a ring...
consider the graph below, the bar of length ζ moving to the right with speed v in a uniform magnetic field B going out the page.
i don't understand why does the textbook say that there is a change in the magnetic fluxΦ? i think the area doesn't change, although it's moving. the original...
Homework Statement
A circular area with a radius of 7.90cm lies in the x-y plane.
A. What is the magnitude of the magnetic flux through this circle due to a uniform magnetic field B = 0.223T that points in the +z direction?
B.What is the magnitude of the magnetic flux through this circle due to...
Homework Statement
A simple pendulum with bob of mass m and conducting wire of length L swings under gravity through an angle 2 theta. The Earth's magnetic field component in the direction perpendicular to swing is B. The maximum potential difference induced across the pendulum is
Homework...
Homework Statement
[/B]
A simple model of a railgun is a metal bar which runs on two long parallel rails. The two rails are connected to a charged capacitor with capacitance C and a resistor with resistance R. After charging, the capacitor can discharge through the circuit. You may assume that...
I wasn't sure where to put this so mods feel free to move,
So this is a problem I'm trying to solve for a masters project and simplified it is this;
I essentially have a stack of magnets all separated by 4mm each magnet is identical and produces a magnetic flux of 17.5 gauss at its centre (all...
Hello, all. I have been working on the following problem and was wondering if someone could check my work and provide some valuable input:
Here is my work:
What do you guys think about my approach to this problem?
My reasoning:
The magnetic force on charge q is
Fm = qv x B
B does not change |v|. Therefore, |Fm| is constant at time t > 0 and Fm is always perpendicular to the direction of movement of charge q. Fm behaves as a centripetal force, and thus the charge moves along the circumference of a...
Magnetic flux linkage = BAN
B=magnetic field strength per unit area
A=Area of conductor moved through the magnetic field
N=Number of coils
I don't understand when my physics textbook says the area of a single coil of wire moved through the magnetic field is π×radius of coil^2 as most of the...
Homework Statement
A long cylinder of radius a with magnetization vector M=M_0*(r/a)^2*a_φ. Find the magnetic flux density inside and outside the cylinder.
Homework Equations
J_m=∇×M
J_ms=M×a_n[/B]
A=(μ_0/4*π)*(∫(J_m/R)dv+∫(J_ms/R)ds)
B=∇×A
The Attempt at a Solution
Basicly what I thought...
We know Total Magnetic Flux B = B_0 + B_m
Where, B_0 is the external field and B_m is the field inside a material.
Now, we get,
B = B_0 + μ_0*M (M is the magnetization)
My question is -
Do I always have to use μ_0 ? If yes then Why?
The material isn't free space, is it?& also
B =...
In the book I'm reading on electromagnetic fields, the authors seem to associate the magnetic flux density B with the electric flux density D, and the magnetic field H with the electric field E.
Now, my question is, wouldn't it make more sense to say B is the analog to E? Because E and B are...
Homework Statement
A circular coil of diameter 24 mm has 40 turns. The coil is placed in a uniform magnetic field of flux density 85 mT with its plane perpendicular to the field lines.
a) i Calculate the area of the coil
ii The flux linkage through the coil.
b) The coil was reversed in a...
Homework Statement
Now, ignore the lengths given in the photo.
Height (y) = .640 meters
Length (z) = 1.18 meters
Base (x) = .320 meters
Magnetic Field (B) = 3.5 Teslas in the +X direction
Homework Equations
The problem is to find the magnetic flux through the surface of the...
Hi to all of you,
As the Biot-Savart-Law is based on experimentations in air, i like to know how to calculate the magnetic flux density in material with much greater permeability, where the circular like shape of the field distribution troughout the vicinity does not apply.
Does anyone has a...
Homework Statement
A bar magnet is held above the center of a wire loop lying in the horizontal plane, as shown in the figure below. The south end of the magnet is toward the loop. After the magnet is dropped, what is true of the current in the resistor as viewed from above? (Select all that...
Homework Statement
The current in a solenoid (you may treat it as a long solenoid of length 2.0 m, turns, and radius 0.5 m) is decreasing at a rate of 1.7 A/s.
What is the EMF at a point .35m inside the solenoid?
Homework Equations
B=N(mu_0*I)/(2a)
where B=magnetic field, N=turns per...
I know that the equation for magnetic flux is \Phi=\int \vec{B} \cdot dA. It seems to me that this is like integrating the density function a rod with respect to x, which simply gives you the mass which is constant. I was wondering whether the same thing applies here: is magnetic flux a constant?
I'm taking E & M II... Would anyone agree that the following statements are true?
An electric field changing in time gives rise to a displacement current.
A magnetic field changing in time gives rise to an electromotive force.
...based on the angle.
Homework Statement
Figure 30-78 shows a wire that has been bent into a circular
arc of radius r = 24.0 cm, centered at O. A straight wire OP can be
rotated about O and makes sliding contact with the arc at P.
Another straight wire OQ completes the conducting...
The scenario is the following, I am given 2 loops with the same radius, r, a distance of d, and same current of I. In the left loop the current goes counter clockwise, in the right loop the current is clockwise. The two loops centers lie on the same axis which are perpendicular to the plane of...
The scenario is the following, I am given 2 loops with the same radius, r, a distance of d, and same current of I. In the left loop the current goes counter clockwise, in the right loop the current is clockwise. The two loops centers lie on the same axis which are perpendicular to the plane of...
Homework Statement
Hi, this is not a homework problem per say but I am just struggling with some concepts related to my homework. I am struggling with the concepts of flux linkage and flux cutting. Are these one and the same thing? The following statement in my book is where my confusion has...
Hi, please could someone help with my confusion over these two qauntities. In class we recently learned that magnetic field strength (B) is the number of flux lines (measured in Webers) per square metre. The magnetic flux on the other hand is the total number of flux lines (measured in Webers)...
Homework Statement
Here is the prompt: http://imgur.com/FTFz0fZ
Homework Equations
Magnetic flux = ∫B dot dA
Net Flux for closed surface = 0
The Attempt at a Solution
For part a:
magnetic flux = (7.74 ^i + 4 ^j + 3 ^k)T * (0.254 m)^2 ^i
= 7.74 T *...
Hello everybody,
I'm studying classical electrodynamics and I'm having a difficulty grasping the concept of EMF.
I'll try to explain what causes my confusion.
Say I've got a conducting loop, an electrical wire, with some resistance R which contracts (or expands) with time.
Let's put that loop...
Why change of magnetic flux with the time through a coil induces current in it?
Please tell me that what happen to charge in the coil if the magnet or electromagnet wave around this? Also, why a constant magnetic flux does not induces current?
Hello
As you know we can find the flux density (B) via vector potential with this equation
So with this equation and solution at first i try to find vector potential completely then use above equation
Problem:
Solution:
my approach:
now we use curl A to find B
we find that
but it...
Homework Statement
Using the divergence theorem, evaluate the total flux of a magnetic field B(r) across the
surface S enclosing a finite, connected volume of space V, and discuss its possible
dependence on the presence of an electric field E(r).
Homework Equations
∇.B=0
The...
Homework Statement
"A metal bar which runs on 2 long parallel rails are connected to a charged capacitor with capacitance C and a resistor with resistance R. Assume no friction and perfect conductors. The rails are cylindrical of radius R separated by distance d. The bar is a distance x...
Homework Statement
The attached picture shows a spool coil on a iron core with an air gap measuring 2.5mm. The spool is coiled by 0.5mm2 with rho cu = 0.0175 Ωmm2 /m. The average winding diameter for the spool is 3.18cm.
Compute the magnetic flux in the spool.
Homework Equations...
Homework Statement
So this is more conceptual than anything. Say there is a wire loop on the x,y axis and a permanent bar magnet above it on the z axis. I understand according to Faraday's law that as the north end of the bar magnet moves towards the loop the magnetic flux is increasing...
Homework Statement
A square wire frame,in the x-y plane, carrying a current 'I' and with side length 'A' is kept at a distance 'A' from the y-axis . Find the magnetic flux through the other half of the plane(not containing the square loop).Homework Equations
The magnetic field due to line...
Hey all,
I'm working on a project now where I am using a solenoid driven at a 10Hz AC current to create a magnetic field on a solid piece of low carbon iron, and then using a smaller solenoid to capture the magnetic flux coming from the iron.
By measuring the phase of the resulting waves...
hi i have some crazy ideas about tornadoes,lightning and storms emitting magnetic flux loops interacting with the Earth's own magnetic properties and do not have enough electrical schooling to know if it is even a possibility. i was hoping i could get a more learned opinion. the thread is...
Homework Statement
Very long wire carrying current I is surrounded by a brass ring of a triangular cross section. (figure attached)
Show that ψ =
μ° I h
------ (b - a ln ((a+b)/b)
2∏b
Homework Equations
A = (μ°I/2∏ * ln x) az (according to one of the solutions, where x is the...