Magnetism and M...

Three identical coils $$A,B,C$$ carrying currents are placed coaxially with their planes parallel to one another. $$A$$ and $$C$$ carry currents as shown in figure. $$B$$ is kept fixed, while $$A$$ and $$C$$ both are moved toward $$B$$ with the same speed. Initially, $$B$$ is equally separated from $$A$$ and $$C$$. The direction of the induced current in the coil $$B$$ is :

An electron moves on a straight line path $$YY'$$ as shown in figure. A coil is kept in the right such that $$YY'$$ is in the plane of the coil. At the instant when the electron gets closest to the coil (neglect self-induction of the coil),

A square coil $$ACDE$$ with it's plane vertical is released from rest in a horizontal uniform magnetic field $$\vec { B } $$ of length $$2L$$ ( as shown in figure). The acceleration of the coil is

A conductor of length $$l$$ and mass $$m$$ can slide without any friction along the two vertical conductors connected at the top through a capacitor (figure). A uniform magnetic field $$B$$ is set up $$\bot $$ to the plane of paper. The acceleration of the conductor

In the space shown a non-uniform magnetic field $$\vec { B } ={B}_{0}(1+x)(\hat {-k } )$$ tesla is present. A closed loop of small resistance, placed in the x-y plane is given velocity $${V}_{0}$$. The force due to magnetic field on the loop is 

Two disc of radius R and 2R are made up of same insulating material both has uniform charge density $$\displaystyle \sigma $$ on one surface. Both the discs are rotated about centrodial axis with constant angular velocity $$\displaystyle \omega  $$ in uniform magnetic field B. If $$\displaystyle E_{1}\: and\: E_{2} $$ are the work done by external agent to provide this energy to the disc Calculate $$\displaystyle E_{2}/2E_{1} $$ :

The potential energy of a bar magnet of magnetic moment $$M$$ placed in a magnetic field of induction $$$$. The position of stable equilibrium of the magnet is at the angular position given by $$\theta$$ equal to:

A coil of radius R carries a current I. Another concentric coil of radius $$\displaystyle r\left( r<<R \right) $$ caries current $$\displaystyle \frac { I }{ 2 } $$. Initially planes of the two coils are mutually perpendicular and both the coils are free to rotate about common diameter. They are released from rest from this position. The masses of the coils are M and m respectively $$\displaystyle \left( m<M \right) $$. During the subsequent motion let $$\displaystyle { K }_{ 1 }$$ and $$\displaystyle { K }_{ 2 }$$ be the maximum kinetic energies of the two coils respectively and let U be the magnitude of maximum potential energy of magnetic interaction of the system of the coils. Choose the correct options.

The coercivity of a magnet is $$3\times 10^{3}Am^{-1}$$. What current should be passed through a solenoid of length $$10\ cm$$ and number of turns $$50$$ that the magnet is demagnetized when inserted in it?

A helium nucleus makes a full rotation of radius 0.8 metre in two seconds. The value of the magnetic field B at the centre of the circle will be: