Electromagnetic Induction — JEE Main PYQs

A coil is suspended in a uniform magnetic field, with the plane of the coil parallel to the magnetic lines of force. When a current is passed through the coil it starts oscillating; it is very difficult to stop. But if an aluminium plate is placed near to the coil, it stops. This …

A boat is moving due east in a region where the earth's magnetic field is $5.0\times 10^{-5}{\text{ NA}}^{-1}{\text{m}}^{-1}$ due north and horizontal. The boat carries a vertical aerial 2 m long. If the speed of the boat is $1.50{\text{ ms}}^{-1}$, the magnitude of the induced emf in …

A fully charged capacitor C with initial charge $q_0$ is connected to a coil of self inductance L at $t=0$. The time at which the energy is stored equally between the electric and the magnetic field is:

A rectangular loop has a sliding connector PQ of length $\ell$ and resistance $\mathrm{R}\Omega$ and it is moving with a speed v as shown. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents ${\mathrm{I}}_1,{\mathrm{I}}_2$ and …

In the circuit shown below, the key K is closed at $\mathrm{t}=0$. The current through the battery is

An inductor of inductance L = 400 mH and resistors of resistances $R_1=2\Omega$ and $R_2=2\Omega$ are connected to a battery of emf 12 V as shown in the figure. The internal resistance of the battery is negligible. The switch S is closed at t = 0. The potential drop across L …

Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross sectional area $\mathrm{A}=10{\mathrm{cm}}^2$ and length $=20\mathrm{cm}$. If one of the solenoids has 300 turns and the other 400 turns , their mutual inductance is ( …

An ideal coil of 10 H is connected in series with a resistance of $5\Omega$ and a battery of 5 V. 2 second after the connection is made the current flowing in amperes in the circuit is

In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with frequency $\omega$ in a magnetic field B. The maximum value of emf generated in the coil is

The flux linked with a coil at any instant 't' is given by

The induced emf at $t=3\mathrm{s}$ is

An inductor $(\mathrm{L}=100\mathrm{mH})$, a resistor $(\mathrm{R}=100\Omega )$ and a battery ($\mathrm{E}=100\mathrm{V}$) are initially connected in series as shown in the figure. After a long time the battery is disconnected after short circuiting the points A and B. The cur …

One conducting U tube can slide inside another as shown in figure, maintaining electrical contacts between the tubes. The magnetic field $B$ is perpendicular to the plane of the figure. if each tube moves towards the other at a constant speed V,

then the emf induced in the cir …

A coil of inductance 300 mH and resistance $2\Omega$ is connected to a source of voltage 2 V. The current reaches half of its steady state value in

A coil having $n$ turns and resistance $R\Omega$ is connected with a galvanometer of resistance $4R\Omega$. This combination is moved in time $t$ seconds from a magnetic field $W_1$ weber to $W_2$ weber. The induced current in the circuit is

In a uniform magnetic field of induction $B$ a wire in the form of semicircle of radius $r$ rotates about the diameter of the circle with angular frequency $\omega$. The axis of rotation is perpendicular to the field. If the total resistance of the circuit is $R$ the mean power g …

A metal conductor of length 1 m rotates vertically about one of its ends at angular velocity 5 radians per second. If the horizontal component of earth's magnetic field is $0.2\times 10^{-4}\mathrm{T}$, then the e.m.f. developed between the two ends of the conductor is