Electromagnetic Induction

Two identical inductors are connected in two different configurations $P$ and $Q$, where a time varying current $l(t)$ is flowing, as shown in the figure. The induced emf between points $a$ and $b$ for configuration $P$ is $E_P$ and that fo...

A conducting loop of finite resistance lies on the $x-y$ plane. There is a constant magnetic field in the $z$ direction. The area of the loop varies with time $t$, as $A=A_0(1+\sin t)$ in appropriate units. The figure that correctly indicat...

Consider a long solenoid of length $I$ and radius $r$. If $n$ is the number of turns per unit length and $\mu_0$ is the permeability of free space, the inductance of the solenoid is :

A rectangular wire loop of sides 8 cm and 3 cm with a small cut, is moving out of a region of uniform magnetic field of magnitude 0.3 T directed normal to the plane of the loop. The emf developed across the cut, if the velocity of the loop ...

$A B$ is a part of an electrical circuit (see figure). The potential difference " $V_A-V_B$ ", at the instant when current $i=2 \mathrm{~A}$ and is increasing at a rate of $1 \mathrm{amp} /$ second is:

Let us consider two solenoids \(A\) and \(B\), made from same magnetic material of relative permeability \(\mu_r\) and equal area of cross-section. Length of \(A\) is twice that of \(B\) and the number of turns per unit length in \(A\) is h...

An emf is generated by an ac generator having 100 turn coil, of loop area \(1 \mathrm{~m}^2\). The coil rotates at a speed of one revolution per second and placed in a uniform magnetic field of \(0.05 \mathrm{~T}\) perpendicular to the axis...

The net magnetic flux through any closed surface is :

The magnetic flux linked to a circular coil of radius R is
\(\phi = 2{t^3} + 4{t^2} + 2t + 5\) Wb
The magnitude of induced emf in the coil at t = 5 s is

A square loop of side 1 m and resistance 1 \(\Omega\) is placed in a magnetic field of 0.5 T. If the plane of loop is perpendicular to the direction of magnetic field, the magnetic flux through the loop is

Two conducting circular loops of radii R1 and R2 are placed in the same plane with their centres coinciding. If R1 >> R2, the mutual inductance M between them will be directly proportional to :

A 800 turn coil of effective area 0.05 m2 is kept. perpendicular to a magnetic filed 5 × 10–5 T. When the plane of the coil is rotated by 90o around any of its coplanar axis in 0.1 s, the emf induced in the coil will be :

In which of the following devices, the eddy current effect is not used?

A long solenoid of diameter 0.1 m has 2 \(\times\) 104 turns per meter. At the centre of the solenoid, a coil of 100 turns and radius 0.01 m is placed with its axis coinciding with the solenoid axis. The current in the solenoid reduces at...

A uniform magnetic field is restricted within a region of rafius r. The magnetic field changes with time at a rate \({{d\overrightarrow B } \over {dt}}\). Loop 1 of radius R > r encloses the region r and loop 2 of radius R is outside the re...

A long solenoid has 1000 turns. When a current of 4 A flows through it, the magnetic flux linked with each turn of the solenoid is 4 \(\times \,{10^{ - 3}}\) Wb. The self-inductance of the solenoid is

An electron moves on a straight line path XY as shown. The abcd is a coil adjacent to the path of electron. What will be the direction of current, if any, induced in the coil ?

A thin semicircular conducting ring (PQR) of radius r is falling with its plane vertical in a horizontal magnetic field B, as shown in the figure.

The potential difference developed across the ring when its speed is \(v\), is

A current of 2.5 A flows through a coil of inductance 5 H. The magnetic flux linked with the coil is

A wire loop is rotated in a magnetic field. The frequency of change of direction of the induced e.m.f. is

A coil of resistance 400 \(\Omega\) is placed in a magnetic field. If the magnetic flux \(\phi\) (Wb) linked with the coil varies with time t (sec) as \(\phi = 50{t^2} + 4\).
The current in the coil at t = 2 sec is

In a coil of resistance 10 \(\Omega\), the induced current developed by changing magnetic flux through it, is shown in figure as a function of time. The magnitude of change in flux through the coil in weber is

The current \(i\) in a coil varies with time as shown in the figure. The variation of induced emf with time would be

A conducting circular loop is placed in a uniform magnetic field, B = 0.025 T with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of 1 mm s\(-\)1. The induced emf when the radius is 2 cm, is...

A conducting circular loop is placed in a uniform magnetic field 0.04 T with its plane perpendicular to the magnetic field. The radius of the loop starts shrinking at 2 mm/s. The induced emf in the loop when the radius is 2 cm is

A rectangular, a square, a circular and an elliptical loop, all in the (x-y) plane, are moving out of a uniform magnetic field with a constant velocity. \(\overrightarrow V = v\widehat i\). The magnetic field is directed along the negative...

A circular disc of radius 0.2 meter is placed in a uniform magnetic field of induction \({1 \over \pi }\left( {{{Wb} \over {{m^2}}}} \right)\) in such a way that its axis makes an angle of 60o with \(\overrightarrow B .\) The magnetic flux ...

A long solenoid has 500 turns. When a current of 2 ampere is passed through it, the resulting magnetic flux linked with each turn of the solenoid is 4 \(\times\) 10\(-\)3 Wb. The self-inductance of the solenoid is

Two coils of self inductance 2 mH and 8 mH are placed so close together that the effective flux in one coil is completely linked with the other. The mutual inductance between these coils is

As a result of change in the magnetic flux linked to the closed loop as shown in the figure, an e.m.f. \(V\) volt is induced in the loop. The work done (joule) in taking a charge Q coulomb once along the loop is

The magnetic flux through a circuit of resistance R changes by an amount \(\Delta\)\(\phi\) in a time \(\Delta\)t. Then the total quantity of electric charge Q that passes any point in the circuit during the time \(\Delta\)t is represen...

For a coil having L = 2 mH, current flow through it is \(I = {t^2}{e^{ - t}}\) then, the time at which emf become zero