Magnetism

There is a ring of radius $r$ having linear charge density $\lambda$ and rotating with a uniform angular velocity $\omega$. The magnitude of the magnetic field produced by this ring at its own centre would be ( $\mu_0=$ permeability of air)...

The magnetic moment of an iron bar is $M$. It is now bent in such a way that it forms an arc section of a circle subtending an angle of $60^{\circ}$ at the centre. The magnetic moment of the arc section is

A circular coil, carrying current, has radius $R$. The distance from the centre of the coil on the axis where the magnetic induction will be $\frac{1}{27}$ th of its value at the centre of the coil is

A particle of charge ' $q$ ' and mass ' $m$ ' moves in a circular orbit of radius ' $r$ ' with angular speed ' $\omega$ '. The ratio of the magnitude of its magnetic moment to that of its angular momentum depends on

A charged particle moving with a velocity \(\vec{v}=v_1 \hat{i}+v_2 \hat{j}\) in a magnetic field \(\vec{B}\) experiences a force \(\vec{F}=F_1 \hat{i}+F_2 \hat{j}\). Here \(v_1, v_2, F_1, F_2\) all are constants. Then $$\overrightarrow{\ma...

A bar magnet falls from rest under gravity through the centre of a horizontal ring of conducting wire as shown in figure. Which of the following graph best represents the speed (v) vs. time (t) graph of the bar magnet?

A wire carrying a steady current I is kept in the x-y plane along the curve \(y=A \sin \left(\frac{2 \pi}{\lambda} x\right)\). A magnetic field B exists in the z-direction. The magnitude of the magnetic force in the portion of the wire bet...

As shown in figure, a rectangular loop of length 'a' and width 'b' and made of a conducting material of uniform cross-section is kept in a horizontal plane where a uniform magnetic field of intensity B is acting vertically downward. Resist...

A horizontal semi-circular wire of radius r is connected to a battery through two similar springs X and Y to an electric cell, which sends current I through it. A vertically downward uniform magnetic field B is applied on the wire, as shown...

A straight wire is placed in a magnetic field that varies with distance x from origin as \(\overrightarrow B = {B_0}\left( {2 - {x \over a}} \right)\widehat k\). Ends of wire are at (a, 0) and (2a, 0) and it carries a current I. If force o...

An electron revolves around the nucleus in a circular path with angular momentum \(\overrightarrow L\). A uniform magnetic field \(\overrightarrow B\) is applied perpendicular to the plane of its orbit. If the electron experiences a torqu...

Two infinite line-charges parallel to each other are moving with a constant velocity v in the same direction as shown in the figure. The separation between two line-charges is d. The magnetic attraction balances the electric repulsion when...

A small bar magnet of dipole moment M is moving with speed v along x-direction towards a small closed circular conducting loop of radius a with its centre O at x = 0 (see figure). Assume x >> a and the coil has a resistance R. Then, which o...

For two types of magnetic materials A and B, variation of \(1\over\chi\) (\(\chi\) : susceptibility) versus temperature T is shown in the figure. Then,

A thin charged rod is bent into the shape of a small circle of radius R, the charge per unit length of the rod being \(\lambda\). The circle is rotated about its axis with a time period T and it is found the magnetic field at a distance d a...

Consider two infinitely long wires parallel to Z-axis carrying same current I in the positive z-direction. One wire passes through the point L at coordinates (\(-\)1, +1) and the other wire passes through the point M at coordinates (\(-\)1,...

A charged particle moves with constant velocity in a region, where no effect of gravity is felt but an electrostatic field E together with a magnetic field B may be present. Then, which of the following cases are possible?

As shown in the figure, a wire is bent to form a D-shaped closed loop, carrying current I, where the curved part is a semi-circle of radius R. The loop is placed in a uniform magnetic field B, which is directed into the plane of the paper. ...

As shown in the figure, a single conducting wire is bent to form a loop in the form of a circle of radius r concentrically inside a square of side a, where a : r = 8 : \(\pi\). A battery B drives a current through the wire. If the battery ...

A square conducting loop is placed near an infinitely long current carrying wire with one edge parallel to the wire as shown in the figure. If the current in the straight wire is suddenly halved, which of the following statements will be tr...

An electric current 'I' enters and leaves a uniform circular wire of radius r through diametrically opposite points. A particle carrying a charge q moves along the axis of the circular wire with speed v. What is the magnetic force experienc...

A metallic loop is placed in a uniform magnetic field B with the plane of the loop perpendicular to B. Under which condition(s) given an emf will be induced in the loop? "If the loop is ............"

A particle with charge q moves with a velocity v in a direction perpendicular to the directions of uniform electric and magnetic fields, E and B respectively, which are mutually perpendicular to each other. Which one of the following gives ...

To which of the following quantities, the radius of the circular path of a charged particle moving at right angles to a uniform magnetic field is directly proportional?

A current 'I' is flowing along an infinite, straight wire, in the positive Z-direction and the same current is flowing along a similar parallel wire 5 m apart, in the negative Z-direction. A point P is at a perpendicular distance 3m from th...

A proton of mass m moving with a speed v (< < c, velocity of light in vacuum) completes a circular orbit in time T in a uniform magnetic field. If the speed of the proton is increased to \(\sqrt 2\) v, what will be time needed to complete ...

A circular loop of radius r of conducting wire connected with a voltage source of zero internal resistance produces a magnetic field B at its centre. If instead, a circular loop of radius 2r, made of same material, having the same cross-sec...

A light charged particle is revolving in a circle of radius r in electrostatic attraction of a static heavy particle with opposite charge. How does the magnetic field B at the centre of the circle due to the moving charge depend on r?

A uniform current is flowing along the length of an infinite, straight, thin, hollow cylinder of radius R. The magnetic field B produced at a perpendicular distance d from the axis of the cylinder is plotted in a graph. Which of the followi...

The magnets of two suspended coil galvanometers are of the same strength so that they produce identical uniform magnetic fields in the region of the coils. The coil of the first one is in the shape of a square of side a and that of the seco...

A particle with charge e and mass m, moving along the X-axis with a uniform speed u, enters a region where a uniform electric field E is acting along the Y-axis. The particle starts to move in a parabola. Its focal length (neglecting any ef...

A proton is moving with a uniform velocity of \({{{10}^6}}\) ms\(-\)1 along the Y-axis, under the joint action of a magnetic field along Z-axis and an electric field of magnitude 2 \(\times\) 104 Vm\(-\)1 along the negative X-axis. If the...

The magnetic field due to a current in a straight wire segment of length L at a point on its perpendicular bisector at a distance r(r >> L)

Two long parallel wires separated by 0.1 m carry currents of 1A and 2A, respectively in opposite directions. A third current-carrying wire parallel to both of them is placed in the same plane such that it feels no net magnetic force. It is ...

If \(\chi\) stands for the magnetic susceptibility of a substance, \(\mu\) for its magnetic permeability and \(\mu\)0 for the permeability of free space, then

An electron enters an electric field having intensity \(E = 3\widehat i + 6\widehat j + 2\widehat k\) Vm\(-\)1 and magnetic field having induction \(B = 2\widehat i + 3\widehat j\) T with a velocity \(v = 2\widehat i + 3\widehat j\) ms\(-\)...

A rectangular coil carrying-current is placed in a non-uniform magnetic field. On that coil, the total

What should be the resistance of an ideal ammeter and an ideal voltmeter?