Question 1 :
Due to the flow of current in a circular loop of radius {tex} R {/tex}, the magnetic induction produced at the centre of the loop is {tex} B {/tex}. The magnetic moment of the loop is {tex} (\mu _ { 0 } = {/tex} permeability constant)

Question 2 :
An electron moves in a circular orbit with a uniform speed {tex} v {/tex}. It produces a magnetic field {tex} B {/tex} at the centre of the circle. The radius of the circle is proportional to<br>

Question 4 :
A magnet makes 30 oscillations per minute at a plane where intensity is 32 T. At another place it takes 1s to complete one oscillation. The value of horizontal intensity at the second place is,

Question 5 :
A particle of mass {tex} 0.6 \mathrm { g } {/tex} and having charge of {tex} 25 \mathrm { nC } {/tex} is moving horizontally with a uniform velocity {tex} 1.2 \times 10 ^ { 4 } \mathrm { ms } ^ { - 1 } {/tex} in a uniform magnetic field, then the value of the magnetic induction is<br>{tex} \left( g = 10 m s ^ { - 2 } \right) {/tex}<br>

Question 6 :
A straight conductor carries a current or {tex} 5 A . {/tex} An electron travelling with a speed of {tex} 5 \times 10 ^ { 6 } \mathrm { m } s ^ { - 1 } {/tex} parallel to the wire at a distance of {tex}0. 1 \mathrm { m } {/tex} from the conductor, experiences a force of

Question 7 :
A cell is connected between two points of a uniformly thick circular conductor. The magnetic field at the centre of the loop will be

Question 8 :
If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity {tex} v {/tex} and an electron is projected along the lines of force, what will happen to proton and electron

Question 9 :
A coil having {tex} N {/tex} turns carry a current {tex} l {/tex} as shown in the figure. The magnetic field intensity at point {tex} P {/tex} is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5dc01d76ec8cf4127b93105c"><br>

Question 10 :
{tex}\mathrm {Assertion}\quad {/tex} :The ion cannot move with a speed beyond a certain limit in a cyclotron. <br>{tex}\mathrm {Reason}\quad {/tex} :As velocity increases time taken by ion increases.

Question 11 :
<font>In vibration magnetometer the time period of suspended bar magnet can be reduced by</font></p>

Question 12 :
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 13 :
A particle charge q and mass m is projected with a velocity {tex}v_{0}{/tex} towards a circular region having uniform magnetic field B perpendicular and into the plane of paper from point P as shown in Fig. 15.56. R is the radius and O is the centre of the circular region. If the line OP makes an angle {tex}\theta{/tex} with the direction of {tex}v_{0}{/tex} then the value of {tex}v_{0}{/tex} so that particle passes through O is <br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abf215637834a58898650" /><br>

Question 14 :
There is a small metallic ring of radius {tex}l_{0}{/tex} having negligible resistance placed perpendicular to a constant magnetic field {tex}B_{0}{/tex}. One end of a rod is hinged at the centre of ring O and other end is placed on the ring. Now rod is rotated with constant angular velocity {tex}\omega_{0}{/tex} by some external agent and circuit is connected as shown in Fig. 15.55, initially switch is open and capacitor is unchanged. If switch {tex}S{/tex} is closed at t = 0, then calculate heat loss from the resistor {tex}R_{2}{/tex} from t = 0 to the instant when voltage across the capacitor becomes {tex}v_{0}{/tex}(Assume plane of ring to be horizontal and friction to be an absent at all the contacts). (Assume, {tex}R_{2} = 2R_{1}{/tex}, {tex}B_{0}l_{0}^{2} \omega_{0} = 4v_{0}){/tex}<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5d5abf175637834a58898649" /><br>

Question 15 :
Statement-1: The core of the transformer is laminated to avoid loss of energy.<br>Statement-2: A laminated metal sheet placed in a changing magnetic field has lower eddy current.

Question 16 :
Due to a small magnet, intensity at a distance x in the end on position is $9$ gauss. What will be the intensity at a distance $\dfrac{x}{2}$ on broad side on position.

Question 18 :
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 19 :
{tex} A , B {/tex} and {tex} C {/tex} are parallel conductors of equal length carrying currents {tex} I , I{/tex} and {tex} 2 I{/tex} respectively. Distance between {tex} A {/tex} and {tex} B {/tex} is {tex} x {/tex}. Distance between {tex} B {/tex} and {tex} C {/tex} is also {tex} x. F _ { 1 } {/tex} is the force exerted by {tex} B {/tex} on {tex} A {/tex} and {tex} F {/tex} is the force exerted by {tex} B {/tex} on {tex} A {/tex}. choose the correct answer<br /><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/JEE%20Main/5dc02043e18860128132d3eb">