Suppose a magnetic monopole qm passes through a resistanceless loop of wire with self-inductance L . What current is induced in the loop?

Short Answer

Expert verified

The induced current in the loop isl=μ0qmL.

Step by step solution

01

Induction law

This law is used to determine the electromotive force (emf) generated due to the interaction between a magnetic field and an electric conductor.

Based on this law, the amount of emf induced in a conductor directly relies upon the changes in the magnetic flux

02

Given information

The magnetic monopole is,qm.

The self-inductance of the resistanceless loop of wire is, L .

03

Current induced in the loop

The generalised equation of Faraday’s law for the resistanceless loop of wire is given by,

×E=-μ0Jm-Bt

Here,represents the electric field,μ0is the permeability of free space,Jmis the current of magnetic charge andBtis the change in magnetic field.

Integrating both sides of equation over the da surface,

(×E).da=-μ0Jm-Bt.daE.dl=-μ0Jm.da-Bt.daε=-μ0Jm.da-ddtB.daε=-μ0lmenc-dΦdt

Here,the induced emf,lmencis induced electro-magnetic current anddΦdtis the change in the magnetic flux.

Also, the induced emf in the wire loop is given by,

ε=-Ldldt

Equating both values,

-Ldldt=-μ0lmenc-dΦdtdldt=-μ0Llmenc+1LdΦdtl=μ0LQm+1LΦ

Here,Qmis the total magnetic charge passing through the surface,Φis the change in flux through the surface.

For theresistanceless loop of wire, and .

l=μ0L×qm+1L×0l=μ0qmL

Hence, the induced current in the loop isl=μ0qmL.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A perfectly conducting spherical shell of radius rotates about the z axis with angular velocity ω, in a uniform magnetic field B=B0Z^. Calculate the emf developed between the “north pole” and the equator. Answer:localid="1658295408106" [12B0ωα2].

Prove Alfven's theorem: In a perfectly conducting fluid (say, a gas of free electrons), the magnetic flux through any closed loop moving with the fluid is constant in time. (The magnetic field lines are, as it were, "frozen" into the fluid.)

(a) Use Ohm's law, in the form of Eq. 7.2, together with Faraday's law, to prove that if σ=and is J finite, then

Bt=×(v×B)

(b) Let S be the surface bounded by the loop (P)at time t , and S'a surface bounded by the loop in its new position (P')at time t+dt (see Fig. 7.58). The change in flux is

=S'B(t+dt)da-SB(t)da

Use ·B=0to show that

S'B(t+dt)da+RB(t+dt)da=SB(t+dt)da

(Where R is the "ribbon" joining P and P' ), and hence that

=dtSBt·da-RB(t+dt)da

(For infinitesimal dt ). Use the method of Sect. 7.1.3 to rewrite the second integral as

dtP(B×v)·dI

And invoke Stokes' theorem to conclude that

dt=S(Bt-×v×B)·da

Together with the result in (a), this proves the theorem.

A square loop of wire, with sides of length a , lies in the first quadrant of the xy plane, with one comer at the origin. In this region, there is a nonuniform time-dependent magnetic field B(y,t)=ky3t2z^ (where k is a constant). Find the emf induced in the loop.

Question: The preceding problem was an artificial model for the charging capacitor, designed to avoid complications associated with the current spreading out over the surface of the plates. For a more realistic model, imagine thin wires that connect to the centers of the plates (Fig. 7.46a). Again, the current I is constant, the radius of the capacitor is a, and the separation of the plates is w << a. Assume that the current flows out over the plates in such a way that the surface charge is uniform, at any given time, and is zero at t = 0.

(a) Find the electric field between the plates, as a function of t.

(b) Find the displacement current through a circle of radius in the plane mid-way between the plates. Using this circle as your "Amperian loop," and the flat surface that spans it, find the magnetic field at a distance s from the axis.

Figure 7.46

(c) Repeat part (b), but this time uses the cylindrical surface in Fig. 7.46(b), which is open at the right end and extends to the left through the plate and terminates outside the capacitor. Notice that the displacement current through this surface is zero, and there are two contributions to Ienc.

A circular wire loop (radius r , resistance R ) encloses a region of uniform magnetic field, B , perpendicular to its plane. The field (occupying the shaded region in Fig. 7.56) increases linearly with time(B=t)An ideal voltmeter (infinite internal resistance) is connected between points P and Q.

(a) What is the current in the loop?

(b) What does the voltmeter read? Answer:[r2/2]

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free