Question 1 : Two identical coaxial circular loops carry current i each circulating in the clockwise direction. If the loops are approaching each other, then

Question 3 : In the non-resonant circuit, what will be the nature of the circuit for frequencies higher than the resonant frequency

Question 5 : A {tex} L C {/tex} circuit is in the state of resonance. If {tex} C = 0.1 \mu F {/tex} and {tex} L = 0.25 \ henry{/tex} . Neglecting ohmic resistance of circuit what is the frequency of oscillations<br>

Question 6 : An ideal transformer has 500 and 5000 turns in primary and secondary winding respectively. If the primary voltage is connected to a 6 V battery then the secondary voltage is

Question 7 : A coil of inductance 300 mH and resistance 2Ω is connected to a source of voltage 2V. The current reaches half of its steady state value in (ln2 = 0.693)

Question 9 : What inductance would be needed to store 1 KWh of energy in a coil carrying a 200 A current

Question 10 : A uniform but time-varying magnetic field {tex} B ( t ) {/tex} exists in a circular region of radius {tex} a {/tex} and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point {tex} P {/tex} at a distance {tex} r {/tex} from the centre of the circular region<br><img style='object-fit:contain' src="https://data-screenshots.sgp1.digitaloceanspaces.com/5dc69ad09a8e92299d4f2629.jpg" /><br>

Question 11 : The graphs given below depict the dependence of two reactive impedances {tex} X {/tex} and {tex} X {/tex} on the frequency of the alternating e.m.f. applied individually to them. We can then say that <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5db8065a0e59867a937383fa">

Question 12 : A conducting rod <em>AB</em> moves parallel to <em>x</em>-axis in the <em>x</em>-<em>y</em> plane. A uniform magnetic field <em>B</em> pointing normally out of the plane exists throughout the region. A force <em>F</em> acts perpendicular to the rod, so that the rod moves with uniform velocity <em>v</em>. The force <em>F</em> is given by (neglect resistance of all the wires) <img style='object-fit:contain' style="max-width:240px;" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5f16c7a0f1a5a149feab9bf0"/>

Question 13 : An inductor {tex} L {/tex} and a capacitor {tex} C {/tex} are connected in the circuit as shown in the figure. The frequency of the power supply is equal to the resonant frequency of the circuit. Which ammeter will read zero ampere <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5db80429faa0567a6e3789fe">

Question 14 : The instantaneous values of current and voltage {tex} \ {/tex} in an ac circuit are {tex} i = 100 \sin 314 \ t{/tex} amp and {tex} e = 200 \sin ( 314 t + \pi / 3 ) V {/tex} respectively. If the resistance is {tex} 1 \Omega {/tex} then the reactance of the circuit will be

Question 15 : The vector diagram of current and voltage for a circuit is as shown. The components of the circuit will be <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5db8063b0e59867a937383e5">

Question 16 : In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of the supply. Which of the following elements are likely to constitute the circuit?

Question 17 : The resonance point in X_L - f and X_C - f curves is-<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e787e1d135d6370e9dc1061' height='138' width='217' >

Question 18 : In a {tex} L C R {/tex} circuit capacitance is changed from {tex} C {/tex} to {tex} 2 C {/tex}. For the resonant frequency to remain unchanged, the inductance should be changed from {tex} L {/tex} to

Question 19 : There is a {tex} 5 \Omega {/tex} resistance in an ac, circuit. Inductance of {tex} 0.1 H {/tex} is connected with it in series. If equation of ac e.m.f is {tex} 5 \sin 50 t {/tex} then the phase difference between current and e.m.f. is

Question 21 : Two circular coils {tex} P {/tex} and {tex} Q {/tex} are arranged coaxially as shown, and the sign convention adopted that currents are taken as positive when flow in the direction of the P to Q <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5b930e2184804a1232209f" /><br>

Question 22 : In the circuit shown here, the point '{tex}\mathrm {C } {/tex}' is kept connected to point '{tex} \mathrm { A } {/tex}' till the current flowing through the circuit becomes constant. Afterward, suddenly, point '{tex}\mathrm { C } {/tex}' is disconnected from point '{tex} \mathrm { A } {/tex}'and connected to point '{tex} \mathrm { B } {/tex}' at time {tex} \mathrm { t } = 0 . {/tex} Ratio of the voltage across resistance and the inductor at {tex} \mathrm { t } = \mathrm { L } / \mathrm { R } {/tex} will be equal to:<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5da8450393616c352cf04465"><br>

Question 23 : A circular coil of radius 5 cm has 500 turns of a wire. The approximate value of the coefficient of self induction of the coil will be

Question 24 : A magnetized wire of moment {tex} M {/tex} is bent into an arc of a circle subtending an angle of {tex} 60 ^ { \circ } {/tex} at the centre, the new magnetic moment is

Question 25 : A wire of irregular shape turning into a circular shape in a magnetic field which is directed into the paper. The direction of induced current is<br><img style='object-fit:contain' src="https://data-screenshots.sgp1.digitaloceanspaces.com/5eb001ff8107bf09261953e1.jpg" />

Question 26 : One conducting U tube can slide inside another as shown in Fig. 15.53, maintaining electrical contacts between the tubes. The magnetic field B is perpendicular to the plane of Fig. 15.53. If each tube moves towards the other at a constant speed v, then the EMF induced in the circuit in terms of B, l, and v, where l is the width of each tube, will be <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abdf004789c4a189c0347" /><br>

Question 27 : Loop {tex} A {/tex} of radius {tex} r ( r << R ) {/tex} moves towards a constant current carrying loop {tex} B {/tex} with a constant velocity {tex} v {/tex} in such a way that their planes are parallel and coaxial. The distance between the loops when the induced EMF in {tex} \operatorname { loop } A {/tex} is maximum is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5b94092184804a12322152" /><br>

Question 28 : In the following circuit the readings of AC voltmeters and ammeters will be respectively-<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e787f1da6b42b703af28381' height='136' width='158' >

Question 29 : The self-induced e.m.f. in a {tex} 0.1 \mathrm { H } {/tex} coil when the current in it is changing at the rate of {tex}200{/tex} ampere/second is

Question 30 : In the figure the flux through the loop perpendicular to the plane of the coil and directed into the paper is varying according to the relation &phi; = 6t² + 7t + 1 where &phi; is in milliweber and t is in second. The magnitude of the emf induced in the loop at t = 2s and the direction of induce current through R are-<br><img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5e787e578ad4296d0cdf7f90' height='156' width='107' >

Question 31 : Five very long, straight wires are bound together to form a small cable. Currents carried by the wires are {tex} I _ { 1 } = 20 A , {tex} I _ { 2 } = - 6 A {/tex}, {tex} I _ { 3 } = 12 A , I _ { 4 } = - 7 A , I _ { 5 } = 18 A . {/tex} The magnetic induction at a distance of {tex} 10 \mathrm { cm } {/tex} from the cable is

Question 32 : A long solenoid of length {tex} L {/tex} has a mean diameter {tex} D . {/tex} It has {tex} n {/tex} layers of windings of {tex} N {/tex} turns each. If it carries a current {tex} " {/tex} the magnetic field at its centre will be

Question 33 : Current {tex}i{/tex} is carried in a wire of length {tex} L {/tex} . If the wire is turned into a circular coil, the maximum magnitude of torque in a given magnetic field {tex} B {/tex} will be

Question 34 : A magnetic needle is kept in a non-uniform magnetic field. It experiences

Question 35 : An electron {tex} \quad {/tex} (mass {tex} \quad = \quad 9.0 \times 10 ^ { - 31 } \mathrm { kg } \quad {/tex} and {tex} \quad {/tex} charge {tex} \left. = 1.6 \times 10 ^ { - 19 } \text { coulomb } \right) {/tex} is moving in a circular orbit in a magnetic field of {tex} 1.0 \times 10 ^ { - 4 } {/tex} weber {tex} / \mathrm { m } ^ { 2 } . {/tex} Its period of revolution is<br>

Question 36 : An electron moves in circular orbit of radius r cm with a speed v m/s in presence of magnetic field B. The energy gained by the electron in going once round the circular orbit is

Question 37 : Two long wires are hanging freely. They are joined first in parallel and then in series and they are connected with a battery. In both cases, which type of force acts between the two wires?

Question 40 : A current-carrying conductor is looped into a circle of radius {tex} 10 \mathrm { cm } . {/tex} The magnetic moment of the current loop becomes {tex} 0.314 \mathrm { A } / \mathrm { m } ^ { 2 } . {/tex} What is the current in the loop?

Question 42 : {tex} \begin{array} { l l } { \text { Assertion }: } & { \text { Cyclotron does not accelerate electron. } } \\ { \text { Reason } } & {: \text { Mass of the electron is very small. } } \end{array} {/tex}

Question 43 : Two concentric circular coils of ten turns each are situated in the same plane. Their radii are {tex} 20 {/tex} and {tex} 40 \mathrm { \ cm } {/tex} and they carry respectively {tex} 0.2 {/tex} and {tex} 0.4\mathrm { \ ampere} {/tex} current in opposite direction. The magnetic field in {tex}\mathrm {weber / {tex} m ^ { 2 }} {/tex} at the centre is

Question 44 : A particle of charge {tex} q {/tex} and mass {tex} m {/tex} moving with a velocity {tex} v {/tex} along the {tex} x {/tex} -axis enters the region {tex} x > 0 {/tex} with uniform magnetic field {tex} B {/tex} along the {tex} k {/tex} direction. The particle will penetrate in this region in the {tex} x {/tex} -direction upto a distance {tex} d {/tex} equal to<br>

Question 45 : A wire carrying current {tex} i {/tex} is shaped as shown. Section {tex} A B {/tex} is a quarter circle of radius {tex} r {/tex}. The magnetic field is directed<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5dc01d0fec8cf4127b93100c"><br>

Question 46 : A current carrying circular loop is freely suspended by a long thread. The plane of the loop will point in the direction

Question 47 : An electron moving with a speed {tex} u {/tex} along the positive {tex} x {/tex} -axis at {tex} y = 0 {/tex} enters a region of uniform magnetic field {tex} \vec { B } = - B _ { 0 } \hat { k } {/tex} which exists<br>to the right of {tex} y {/tex} -axis. The electron exits from the region after some time with the speed {tex} v \text { at co-ordinate } y ,then<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5dc024b2e18860128132d6a2">

Question 48 : Two straight long conductors {tex} A O B {/tex} and {tex} C O D {/tex} are perpendicular to each other and carry currents {tex} i _ { 1 } {/tex} and {tex} i _ { 2 } . {/tex} The magnitude of the<br>magnetic induction at a point {tex} P {/tex} at a distance {tex} a {/tex} from the point {tex} O {/tex} in a direction perpendicular to the plane {tex} A C B D {/tex} is<br>

Question 49 : A particle having a charge of {tex} 10.0 \mu C {/tex} and mass {tex} 1 \mu g {/tex} moves in a circle of radius {tex} 10 {/tex} {tex} \mathrm { cm } {/tex} under the influence of a magnetic field of of induction {tex} 0.1 \ T . {/tex} When the particle is at a point {tex} P , \mathrm { a } {/tex} uniform electric field is switched on so that the particle starts moving along the tangent with a uniform velocity. The electric field is<br> <img style='object-fit:contain' src='https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5dc27363e18860128132d9d9' />

Question 50 : Three long, straight and parallel wires {tex} C , D , {/tex} and {tex} G {/tex} carrying currents are arranged as shown in Fig. 15.50 . The force experienced by a 25{tex} \mathrm { cm } {/tex} length of wire {tex} C {/tex} is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abdde04789c4a189c0338" /><br>

Question 51 : There are two current carrying planar coils each made from identical wires of length L. $C_1$ is circular (radius R) and $C_2$ is square(side a). They are so constructed that they have same frequency of oscillation when they are place in the same uniform magnetic field $\vec{B}$ and carry the same current. Find a in terms of R.

Question 52 : A charge particle enters into a region containing uniform electric field {tex} ( E ) {/tex} and uniform magnetic field {tex} ( B ) {/tex} along {tex} x {/tex} -axis and {tex} y {/tex} -axis, respectively. If it passes the region undeviated, the velocity of charge particle is given by

Question 53 : <font>If a magnetic material is having magnetic susceptibility (</font><font><i>X</i></font><font>) = -1, then the relative magnetic permeability (</font><img style='object-fit:contain' align="bottom" height="23" src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5fc0ef87a89a512aab2122bf" width="18"/> <font>) and type of magnetic material is</font></p> <p align="justify"> <font color="#000000">

Question 54 : </font><font color="#000000"><font>The hysteresis cycle for the material of a transformer core is</font></font></p> <p align="justify"> <font color="#000000">

Question 55 : A very long current carrying wire is placed along {tex} z {/tex} -axis having current of magnitude {tex} i _ { 1 } {/tex} towards nega- tive {tex} z {/tex} -axis. A semicircular wire of radius {tex} R {/tex} and having current {tex} i _ { 2 } {/tex} is placed in {tex} x - y {/tex} plane, such that line joining two end points of the semicircular wire passes through long wire as shown in Fig. 15.57 . Nearest distance of semicircular wire from long wire is {tex} R {/tex} . Net magnetic force on semicircular wire will be<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abf285637834a58898655" /><br>

Question 56 : Three particles each of mass {tex} m {/tex} and charge {tex} q {/tex} are attached to the vertices of a triangular frame, made up of three light rigid rods of equal length {tex} L {/tex} . The frame is rotated at constant angular speed {tex} \omega {/tex} about an axis perpendicular to the plane of the triangle and passing through its centre. The ratio of the magnetic moment of the system and its angular momentum about the axis of rotation is

Question 57 : When a long wire carrying a steady current is bent into a circular coil of one turn, the magnetic induction at its centre is {tex} B {/tex} . When the same wire carrying the same current is bent to form a circular coil of {tex} n {/tex} turns of a smaller radius, the magnetic induction at the centre will be<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abdf804789c4a189c034c" /><br>

Question 58 : <font>Force between two identical bar magnets whose centers are </font><font><i>rmetre</i></font><font> apart is 4.8 </font><font><i>N</i></font><font> when their axes are in the same line. If the separation is increases to 2</font><font><i>rmetre</i></font><font>, the force between them is reduced to</font></p>

Question 59 : Two parallel beams of electrons are moving with small velocities (v << c) in same direction, then there will be-

Question 60 : <font>A compass needle placed at a distance r from a short magnet in tanA position shows a deflection of 60</font>^{<font>0</font>}<font>. If the distance is increased to r(3)</font>^{<font>1/3</font>}<font>, then the deflection of the compass needle is -</font></p>