Induced Definition and 925 Threads

Homework Statement I don't understand why the answer in this problem is choice A. http://grephysics.net/ans/9277/57 I'm confused. Lets say the semi circle is FULLY outside of the circle. For awhile after that, the semi circle would be accelerating the rate at which a certain % of it is...

i am just being curious about some details about how laser can induce charges inside a glass bulk? Does anyone else have more knowledge on this?

In the classic problem of the induced EMF in a moving conductor (as in the picture above), the calculation for the induced EMF is as follows E=\frac{d\Phi_B}{dt}=\frac{d(BA)}{dt}=\frac{Bd(A)}{dt}=\frac{Bd(Lx)}{dt}=\frac{BLdx}{dt}=BLv. The derivation assumes that the magnetic field B is...

When a positive point charge q is brought close to a neutral conducting spherical shell then negative charges will be induced on the part of the shell closer to q and equal positive charges will appear on side of the shell farther from q.I understand this part. But if the conducting spherical...

Why will there not be an induced current in a field parallel to a current carrying wire?

This is discussed in Weinberg's Quantum Theory of Fields, in the chapter on Relativistic Quantum Mechanics. The point I am somewhat confused about occurs on page 63 - 64, if you have the book. He operates on a single particle state with the unitary homogeneous lorentz transformation...

please elaborate their difference in your own word.. thanks! (SURVEY)

If an arbitrary shaped conductor is moving through a steady-state magnetic field, \mathbf{B}(\mathbf{r}), is it true that the field induced in the conductor will be proportional to \mathbf{B}? IE: \mathbf{B}_{induced}(\mathbf{r}) = M \mathbf{B}(\mathbf{r}) where M is a 3-by-3 constant...

If a wire moves with some constant velocity (4 m/s for example in the diagram) parallel to the direction of the wire itself (unlike in most physics problems in which you drag a wire 'sideways' or perpendicular to the direction of the wire) but still perpendicular to the magnetic field, what is...

These are 2 straight wires parallel for 3 inches. Specifically a 6AWG and 12AWG separated approximately 2 inches. A surge current enters on the 6AWG which has a rising edge of 2500A/us. This is for a surge device ... I have been working in plain old RF for too long to be certain that I using...

Homework Statement A hollow spherical conducting shell is suspended in air by an insulating string, so that the sphere is electrically isolated. The total charge on the conductor is -6 μC. If an additional point charge of +2μC is placed in the hollow region inside the shell, what is the total...

Assuming there is a time varying magnetic field (B) , how to determine the direction of the induced electric field due to B. and to which parameters does it depend?

Can anyone tell me the site or give information on these i have small doubts in that so can anyone give exact answer When a sinusoidal input is applied to circular coil of N turns what is the magnetic field generated around it and what is the induced voltage in an other circular coil of...

A magnetic field of B=0.5B0z^ is present when a loop with radius r is rotated around the y-axis with angular velocity of w=9 rad/s. What is the induced emf? Well: flux = SB*dA = SBdAcosq(t) = Bcosq(t)SdA = 0.5B0*pi*r^2cosq(t) d(flux)/dt = 0.5B0*pi*r^2*-sinq(t)*dq(t)/dt =...

Homework Statement A point charge q is placed at a distance ##r## from the centre O of a uncharged spherical shell of inner radius ##R## and outer radius ##2R##. The distance ##r<R##. Find the electric potential at the centre of shell.Homework Equations The Attempt at a Solution The charges...

Hi all, Perhaps I'm asking the wrong question but I am wondering about the relationship between different definitions of, for the sake of argument, the torus. We can define it parametrically (or as a single constraint) and from there work out the induced metric as with any surface. But...

Homework Statement An aeroplane in horizontal flight has a wing span of 50 m and is traveling due north at a speed of 500 kmph. Calculate the emf induced between the wing tips of the aeroplane. The value of the vertical component of the Earth’s magnetic field is 5.5 x 10-5 T. What...

Homework Statement A small, 1.60-mm-diameter circular loop with R = 1.40×10−2Ω is at the center of a large 120-mm-diameter circular loop. Both loops lie in the same plane. The current in the outer loop changes from 1 A to -1 A in 8.00×10−2 s. What is the induced current in the inner...

How to determine the direction of emf induced in an alternator without the need to look at the graph. (i.e) using Lenz's Law or Faraday's Laws of determining the direction? Consider for example the instant when B and dA are perpendicular and no flux is present? Thanks for helping!

Homework Statement See attachment. Homework Equations The Attempt at a Solution For the first part: (B' and x' are B subscript 0 and x subscript 0 respectively.) \phi=BA=B'xl=B'l(L+x'cos(ωt)) EMF=-d\phi/dt=-B'ωlx'sin(ωt) Therefore V=-EMF=B'ωlx'sin(ωt) So...

Homework Statement A point charge Q is placed at a perpendicular distance a from an infinite planar LIH (linear, isotropic, homogeneous) dielectric of relative permittivity ε. By considering the normal component of the electric field at an arbitrary point just inside the dielectric to be the...

Can any ine tell from where i can get this information If a single turn circular coil generates a magnetic field around it how can we calculate the induced voltage in a single turn circular coil located at a distance of d

Dear colleagues, My question here refers to the EMF induced in an incomplete ring that is stationary amidst a time dependent magnetic field. We know from Faraday's law that EMF is created upon changing the magnetic flux, either by changing the intensity of the field, or by changing the...

Homework Statement so there's two solenoids on the same axis of symmetry, and the smaller one inside the larger one has a resistance of 11 ohms, 1000 turns, and radius .02 meters. the outer solenoid has n 18000 turns per meter, and had a current that is increasing at a constant rate with...

Homework Statement A small, 1.60-mm-diameter circular loop with R = 1.10×10−2Ω is at the center of a large 120-mm-diameter circular loop. Both loops lie in the same plane. The current in the outer loop changes from + 1A to -1A in 8.00×10^−2s . What is the induced current in the inner loop...

Homework Statement I'm working on induced currents/b-fields from Lenz's Laws and two different problems use the same equation but one has an extra variable and I don't know when to add this equation. Problem 1: In a physics laboratory experiment, a coil with 180 turns enclosing an area of...

Homework Statement I'm working on induced currents/b-fields from Lenz's Laws and two different problems use the same equation but one has an extra variable and I don't know when to add this equation. Problem 1: In a physics laboratory experiment, a coil with 180 turns enclosing an area of...

A charge Q is kept at a distance x from one of the plates of a parallel capacitor having plates d distance apart with cross section area A.The whole system is earthed.Find the value of induced charges on both the plates. I tried putting the sum of induced charges equal to Q and balancing...

Homework Statement The magnetic field strength at the South Pole is around 66μT, and magnetic field lines point out of the Earth perpendicular to the surface. The sled is a metal square of side 0.95 m (with non-conducting wooden slats in between). What is the magnetic flux through the sled...

Homework Statement Estimate the fundamental frequency of resonance sound induced by blowing on the open end of a half liter bottle Homework Equations f= 1c/4L The Attempt at a Solution i don't know the length of L, what's half liter bottle ..? What does it tell you? 2 x f1?

Homework Statement I have attached the two questions. the first has a diagram. 1. Find the MAX Induced EMF (in volts) in the loop by the changing current? 2. What is the magnitude of the EMF induced in the loop by the changing current at t=.8 (seconds) answer in Volts? Homework...

When you use Faraday's law to calculate the induced electric field due to a changing magnetic flux, you integrate over a loop defined by the circuit you're interested in. Why is the electric field confined to the circuit? Couldn't I just pick a random loop in space and integrate over that...

Homework Statement Homework Equations The Attempt at a Solution Their answer assumes that the B-field is perpendicular to the velocity at all times, which is clearly not the case. And in the next part of the question, won't the answer be zero? since now velocity is parallel to B-field? (So...

Homework Statement http://img805.imageshack.us/img805/6030/82154948.png Find Vemf (between points 1 and 2) and it's polarity at t = 0. I have omitted details because my question is specifically on the polarity.Homework Equations Lenz's law: An induced electromotive force (emf) always gives...

Because according to Faraday's law there should be a change in the flux to generate electric potential for a current to take place. But in that case no flux change happens. This can be reasonably explained by Lorentz force(charge separation due to radial Lorentz force) but can we still apply...

Homework Statement It is often discussed that a changing magnetic field will create a non-conservative electric field, which would then induces an EMF and hence an induced current, but what happens when we connect voltmeters? Consider putting a circular loop of wire with some resistance in...

Homework Statement Let R be an arbitrary ring, B and B' be left R-modules, and i: B' \to B be an R-module morphism. Show that if the induced map i^*: \operatorname{Hom}_R(B,M) \to \operatorname{Hom}(B',M) is surjective for every R-module M, then i: B' \to B is injective. The...

A flat, rectangular coil of dimensions L and w is pulled with uniform speed v through a uniform magnetic field B with the plane of its area perpendicular to the field (the figure (Figure 1) ).How is the emf zero? My reasons as to why it's zero: the trig part forces the problem to be zero...

Hi I'm a first year undergrad student studying Electronics. I am really interested in creating a working Laser Induced Breakdown Spectroscopy(LIBS) setup in my summer break which is June and July. I'm reading about it these days, although still scratching the surface. I'm confused whether I'll...

Homework Statement A coil of wire with N turns is placed around the a long solenoid with n turns per unit length carrying a current I as shown below, A)If a current I flows through the solenoid, derive an expression for the magnetic flux through the coil and explain why the size and shape...

Hi, Two questions I'm finding it hard to get my head around with inductors... Say we have an increasing current, this is going to cause an increase in flux in one direction, which will induce an emf to drive a current which produces a magnetic field to oppose the change in flux. Than doing...

∇x E≠0 for an induced electric field whereas for field produced by static charges we have ∇x E=0. This is a very huge difference in the property of a vector field,then why do we call both of them electric field ?

2. Three loops of wire move near a long straight wire carrying a current as in the following figure. (a) What is the direction of the induced current, if any, in loop A? a. clockwise b. counterclockwise c. No current is induced. (ANSWER) WHY IS "C" THE ANSWER? I don't understand...

Homework Statement There's a infinitely-long straight line in vacuum goes through space, carrying a current which is time-dependent. What is the magnetic field induced by the curent? B, vector, the magnetic field E, vector, the electric field J, vector, the current density ρ, scalar, the...

Hi, I'm a bit confused by induced drag on an aerofoil and hoping somebody can clear it up for me. I understand that as air slips around the edges of the wing due to the pressure differential between the top and the bottom surfaces, the angle of attack at the ends of the wings is...

All I understand clearly that if a metal sphere is charged then the charges must reside on the surface because that is the only way there is no electric field within the metal. However if you imagine a neutral metal sphere, and let's say it is suddenly enclosed by a uniformly charged metal...

Understanding the physics of "induced charge" over a perfect conductor When we put a perfect conductor, let's say a sphere inside an external electric field, there will be a surface charge distribution different from 0 even though the sphere is electrically neutral. I don't really understand...

Homework Statement The magnetic field shown in Figure P20.61 has a uniform magnitude of 29.00 mT directed into the paper. The initial diameter of the kink is 0.30 cm. (a) The wire is quickly pulled taut, and the kink shrinks to a diameter of zero in 55.00 ms. Determine the average...

1. A solenoid of length 3.64 cm and diameter 0.914 cm is wound with 170 turns per cm. If the current is decreasing at a rate of 36.3 A/s, what is the induced emf in one of the windings? this is what I did: Length of the solenoid l = 3.64cm = (3.64...

Hello Team, I have a rubber (harness A of 54 and elongation at break of 100%) on which 30N of force is applied over 45mm2 of ares. I would like to know the strain induced in the rubber against the force. The problem here is i could not find the exact Young's modulus value for this material. But...