Electromagnetic Induction · Physics · NEET

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 :

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 for configuration $Q$ is $E_Q$. The ratio $E_P / E_Q$ is:

[Neglect the effect of mutual inductance.]

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 indicates the qualitative behaviour of the power $P$ dissipated in the loop as a function of time 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 is $2 \mathrm{~cm} \mathrm{~s}^{-1}$, in a direction normal to the shorter side of the loop, will be :

$A B$ 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 half that of $$B$$. The ratio of self inductances of the two solenoids, $$L_A: L_B$$ is

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 of rotation of the coil. The maximum value of emf is :-

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