Electromagnetic Induction

133 questions · Physics · JEE Main

Electromagnetic Induction

133 questions · Physics · JEE Main

Conductor wire ABCDE with each arm 10 cm in length is placed in magnetic field of $\frac{1}{2}$ Tesla, perpendicular to its plane. When conductor is pulled towards right with constant velocity of $10 cm / s$ ,… Includes diagram2025 · 4 Apr · Shift 1 · Q74 · Numerical
A rectangular metallic loop is moving out of a uniform magnetic field region to a field free region with a constant speed. When the loop is partially inside the magnate field, the plot of magnitude of induced emf $(ε)$ with time $(t)$ …2025 · 22 Jan · Shift 2 · Q58 · MCQ
Regarding self-inductance: A. The self-inductance of the coil depends on its geometry. B. Self-inductance does not depend on the permeability of the medium. C. Self-induced e.m.f. opposes any change in the current in a circuit. D.…2025 · 23 Jan · Shift 1 · Q68 · MCQ
In the given circuit the sliding contact is pulled outwards such that electric current in the circuit changes at the rate of $8 A / s$ . At an instant when R is $12Ω$ , the value of the current in the circuit will be… Includes diagram2025 · 23 Jan · Shift 1 · Q73 · Numerical
A uniform magnetic field of 0.4 T acts perpendicular to a circular copper disc 20 cm in radius. The disc is having a uniform angular velocity of 10 $π$ rad s-1 about an axis through its centre and perpendicular to the disc. What is the…2025 · 28 Jan · Shift 2 · Q54 · MCQ
A conducting bar moves on two conducting rails as shown in the figure. A constant magnetic field B exists into the page. The bar starts to move from the vertex at time t = 0 with a constant velocity. If the induced EMF is E ∝ tn, then… Includes diagram2025 · 28 Jan · Shift 2 · Q75 · Numerical
A coil of area A and N turns is rotating with angular velocity $ω$ in a uniform magnetic field $B$ about an axis perpendicular to $B$ . Magnetic flux $φ$ and induced emf $ε$ across it, at an instant when $B$ …2025 · 29 Jan · Shift 1 · Q61 · MCQ
Consider I1 and I2 are the currents flowing simultaneously in two nearby coils 1 & 2, respectively. If L1 = self inductance of coil 1, M12 = mutual inductance of coil 1 with respect to coil 2, then the value of induced emf in coil 1…2025 · 29 Jan · Shift 1 · Q62 · MCQ
A rectangular loop of sides $12 cm$ and $5 cm$ , with its sides parallel to the $x$ -axis and $y$ -axis respectively, moves with a velocity of $5 cm / s$ in the positive $x$ axis direction, in a space…2024 · 1 Feb · Shift 1 · Q81 · Numerical
A transformer has an efficiency of $80%$ and works at $10 V$ and $4 kW$ . If the secondary voltage is $240 V$ , then the current in the secondary coil is :2024 · 1 Feb · Shift 2 · Q78 · MCQ
A coil of 200 turns and area $0.20 m^{2}$ is rotated at half a revolution per second and is placed in uniform magnetic field of $0.01 T$ perpendicular to axis of rotation of the coil. The maximum voltage generated in the…2024 · 1 Feb · Shift 2 · Q88 · Numerical
Two conducting circular loops A and B are placed in the same plane with their centres coinciding as shown in figure. The mutual inductance between them is: Includes diagram2024 · 5 Apr · Shift 1 · Q70 · MCQ
The current in an inductor is given by $I = (3 t + 8)$ where $t$ is in second. The magnitude of induced emf produced in the inductor is $12 mV$ . The self-inductance of the inductor $mH$ …2024 · 5 Apr · Shift 2 · Q88 · Numerical
In a coil, the current changes from $- 2 A$ to $+ 2 A$ in $0.2 s$ and induces an emf of $0.1 V$ . The self inductance of the coil is :2024 · 6 Apr · Shift 2 · Q67 · MCQ
A square loop of side $15 cm$ being moved towards right at a constant speed of $2 cm / s$ as shown in figure. The front edge enters the $50 cm$ wide magnetic field at $t = 0$ . The value of induced emf in… Includes diagram2024 · 9 Apr · Shift 2 · Q78 · MCQ
A rectangular loop of length $2.5 m$ and width $2 m$ is placed at $6 0^{\circ}$ to a magnetic field of $4 T$ . The loop is removed from the field in $10 sec$ . The average emf induced in the loop during…2024 · 27 Jan · Shift 1 · Q72 · MCQ
Two coils have mutual inductance $0.002 H$ . The current changes in the first coil according to the relation $i = i_{0} sin ω t$ , where $i_{0} = 5 A$ and $ω = 50 π$ rad/s. The…2024 · 27 Jan · Shift 1 · Q83 · Numerical
Match List I with List II Choose the correct answer from the options given below: Includes table2024 · 29 Jan · Shift 1 · Q74 · MCQ
A square loop of side $10 cm$ and resistance $0.7Ω$ is placed vertically in east-west plane. A uniform magnetic field of $0.20 T$ is set up across the plane in north east direction. The magnetic field is decreased to zero…2024 · 29 Jan · Shift 1 · Q85 · Numerical
A horizontal straight wire $5 m$ long extending from east to west falling freely at right angle to horizontal component of earths magnetic field $0.60 \times 1 0^{- 4} Wbm^{- 2}$ . The instantaneous value of emf induced in…2024 · 29 Jan · Shift 2 · Q90 · Numerical
A ceiling fan having 3 blades of length $80 cm$ each is rotating with an angular velocity of 1200 $rpm$ . The magnetic field of earth in that region is $0.5 G$ and angle of dip is $3 0^{\circ}$ . The emf induced…2024 · 30 Jan · Shift 1 · Q90 · Numerical
Match List I with List II Choose the correct answer from the options given below: Includes table2024 · 30 Jan · Shift 2 · Q69 · MCQ
A coil is places perpendicular to a magnetic field of $5000 T$ . When the field is changed to $3000 T$ in $2 s$ , an induced emf of $22 V$ is produced in the coil. If the diameter of the coil is $0.02 m$ …2024 · 31 Jan · Shift 1 · Q73 · MCQ
A small square loop of wire of side $l$ is placed inside a large square loop of wire of side $L (L = l^{2})$ . The loops are coplanar and their centers coincide. The value of the mutual inductance of the system is $x \times 1 0^{- 7} H$ …2024 · 31 Jan · Shift 1 · Q88 · Numerical
The magnetic flux $ϕ$ (in weber) linked with a closed circuit of resistance $8Ω$ varies with time (in seconds) as $ϕ = 5 t^{2} - 36 t + 1$ . The induced current in the circuit at $t = 2 s$ is A.2024 · 31 Jan · Shift 2 · Q89 · Numerical
A coil is placed in magnetic field such that plane of coil is perpendicular to the direction of magnetic field. The magnetic flux through a coil can be changed : A. By changing the magnitude of the magnetic field within the coil. B. By…2023 · 1 Feb · Shift 2 · Q51 · MCQ
The induced emf can be produced in a coil by A. moving the coil with uniform speed inside uniform magnetic field B. moving the coil with non uniform speed inside uniform magnetic field C. rotating the coil inside the uniform magnetic field…2023 · 6 Apr · Shift 1 · Q44 · MCQ
Two concentric circular coils with radii $1 cm$ and $1000 cm$ , and number of turns 10 and 200 respectively are placed coaxially with centers coinciding. The mutual inductance of this arrangement will be $\times 1 0^{- 8} H$ …2023 · 6 Apr · Shift 2 · Q65 · Numerical
Certain galvanometers have a fixed core made of non magnetic metallic material. The function of this metallic material is2023 · 8 Apr · Shift 1 · Q50 · MCQ
An emf of $0.08 V$ is induced in a metal rod of length $10 cm$ held normal to a uniform magnetic field of $0.4 T$ , when moves with a velocity of:2023 · 8 Apr · Shift 2 · Q43 · MCQ
Given below are two statements: Statement I : If the number of turns in the coil of a moving coil galvanometer is doubled then the current sensitivity becomes double. Statement II : Increasing current sensitivity of a moving coil…2023 · 10 Apr · Shift 1 · Q47 · MCQ
A 1 m long metal rod XY completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0.15 T. If the resistance of the circuit is 5 $Ω$ , the force needed to move the rod in… Includes diagram2023 · 10 Apr · Shift 1 · Q68 · Numerical
A square loop of side $2.0 cm$ is placed inside a long solenoid that has 50 turns per centimetre and carries a sinusoidally varying current of amplitude $2.5 A$ and angular frequency $700 ~\mathrm{rad}…2023 · 10 Apr · Shift 2 · Q60 · Numerical
The magnetic field B crossing normally a square metallic plate of area $4 m^{2}$ is changing with time as shown in figure. The magnitude of induced emf in the plate during $t = 2 s$ to $t = 4 s$ , is $mV$ … Includes diagram2023 · 11 Apr · Shift 1 · Q70 · Numerical
Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$ Assertion A: A bar magnet dropped through a metallic cylindrical pipe takes more time to come down compared to a…2023 · 11 Apr · Shift 2 · Q47 · MCQ
A metallic cube of side $15 cm$ moving along $y$ -axis at a uniform velocity of $2 ms^{- 1}$ . In a region of uniform magnetic field of magnitude $0.5 T$ directed along $z$ -axis. In equilibrium the potential… Includes diagram2023 · 11 Apr · Shift 2 · Q65 · Numerical
A conducting circular loop is placed in a uniform magnetic field of $0.4 T$ with its plane perpendicular to the field. Somehow, the radius of the loop starts expanding at a constant rate of $1 mm / s$ . The…2023 · 12 Apr · Shift 1 · Q68 · Numerical
An insulated copper wire of 100 turns is wrapped around a wooden cylindrical core of the cross-sectional area $24 cm^{2}$ . The two ends of the wire are connected to a resistor. The total resistance in the circuit is $12 Ω$ .…2023 · 13 Apr · Shift 2 · Q68 · Numerical
$12 V$ battery connected to a coil of resistance $6Ω$ through a switch, drives a constant current in the circuit. The switch is opened in $1 ms$ . The emf induced across the coil is $20 V$ . The inductance…2023 · 15 Apr · Shift 1 · Q62 · MCQ
A $20 cm$ long metallic rod is rotated with $210 rpm$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic…2023 · 15 Apr · Shift 1 · Q70 · Numerical
A conducting circular loop of radius $\frac{10}{π}$ cm is placed perpendicular to a uniform magnetic field of 0.5 T. The magnetic field is decreased to zero in 0.5 s at a steady rate. The induced emf in the circular loop at 0.25 s…2023 · 24 Jan · Shift 1 · Q54 · MCQ
A metallic rod of length 'L' is rotated with an angular speed of ' $ω$ ' normal to a uniform magnetic field 'B' about an axis passing through one end of rod as shown in figure. The induced emf will be : Includes diagram2023 · 24 Jan · Shift 2 · Q55 · MCQ
Three identical resistors with resistance R = 12 $Ω$ and two identical inductors with self inductance L = 5 mH are connected to an ideal battery with emf of 12 V as shown in figure. The current through the battery long after the… Includes diagram2023 · 24 Jan · Shift 2 · Q73 · Numerical
A wire of length 1m moving with velocity 8 m/s at right angles to a magnetic field of 2T. The magnitude of induced emf, between the ends of wire will be .2023 · 25 Jan · Shift 2 · Q51 · MCQ
Find the mutual inductance in the arrangement, when a small circular loop of wire of radius ' $R$ ' is placed inside a large square loop of wire of side $L (L ≫ R)$ . The loops are coplanar and their centres coincide : Includes diagram2023 · 29 Jan · Shift 1 · Q50 · MCQ
A certain elastic conducting material is stretched into a circular loop. It is placed with its plane perpendicular to a uniform magnetic field B = 0.8 T. When released the radius of the loop starts shrinking at a constant rate of 2 cms $^{- 1}$ …2023 · 29 Jan · Shift 1 · Q72 · Numerical
A square loop of area 25 cm $^{2}$ has a resistance of 10 $Ω$ . The loop is placed in uniform magnetic field of magnitude 40.0 T. The plane of loop is perpendicular to the magnetic field. The work done in pulling the loop out of the…2023 · 29 Jan · Shift 2 · Q48 · MCQ
As per the given figure, if $\frac{dI}{dt} = - 1 A / s$ then the value of $V_{AB}$ at this instant will be $V$ . Includes diagram2023 · 30 Jan · Shift 1 · Q65 · Numerical
Spherical insulating ball and a spherical metallic ball of same size and mass are dropped from the same height. Choose the correct statement out of the following {Assume negligible air friction}2023 · 31 Jan · Shift 1 · Q50 · MCQ
A circular coil of 1000 turns each with area 1m2 is rotated about its vertical diameter at the rate of one revolution per second in a uniform horizontal magnetic field of 0.07T. The maximum voltage generation will be …2022 · 24 Jun · Shift 2 · Q69 · Numerical
A small square loop of wire of side $l$ is placed inside a large square loop of wire $L (L >> l)$ . Both loops are coplanar and their centres coincide at point $O$ as shown in figure. The mutual inductance of… Includes diagram2022 · 25 Jul · Shift 1 · Q53 · MCQ
The electric current in a circular coil of 2 turns produces a magnetic induction B1 at its centre. The coil is unwound and in rewound into a circular coil of 5 tuns and the same current produces a magnetic induction B2 at its centre. The…2022 · 25 Jul · Shift 2 · Q46 · MCQ
Magnetic flux (in weber) in a closed circuit of resistance 20 $Ω$ varies with time t(s) at $ϕ$ = 8t2 $-$ 9t + 5. The magnitude of the induced current at t = 0.25 s will be mA.2022 · 25 Jul · Shift 2 · Q70 · Numerical
The current in a coil of self inductance 2.0 H is increasing according to I = 2 sin(t2) A. The amount of energy spent during the period when current changes from 0 to 2 A is J.2022 · 25 Jun · Shift 1 · Q69 · Numerical
In a coil of resistance $8 Ω$ , the magnetic flux due to an external magnetic field varies with time as $ϕ = \frac{2}{3} (9 - t^{2})$ . The value of total heat produced in the coil, till the flux becomes zero, will be $J$ …2022 · 26 Jul · Shift 2 · Q64 · Numerical
The magnetic flux through a coil perpendicular to its plane is varying according to the relation $ϕ = (5 t^{3} + 4 t^{2} + 2 t - 5)$ Weber. If the resistance of the coil is 5 ohm, then the induced current through the coil at t = 2 s will…2022 · 26 Jun · Shift 1 · Q52 · MCQ
A 10 $Ω$ , 20 mH coil carrying constant current is connected to a battery of 20 V through a switch. Now after switch is opened current becomes zero in 100 $μ$ s. The average e.m.f. induced in the coil is V.2022 · 26 Jun · Shift 1 · Q63 · Numerical
Two coils of self inductance L1 and L2 are connected in series combination having mutual inductance of the coils as M. The equivalent self inductance of the combination will be : Includes diagram2022 · 26 Jun · Shift 2 · Q59 · MCQ
A metallic conductor of length 1 m rotates in a vertical plane parallel to east-west direction about one of its end with angular velocity 5 rad s $-$ 1. If the horizontal component of earth's magnetic field is 0.2 $\times$ 10 $-$ 4 T, then…2022 · 26 Jun · Shift 2 · Q60 · MCQ
A conducting circular loop is placed in $X - Y$ plane in presence of magnetic field $B = (3 t^{3} \hat{j} + 3 t^{2} \hat{k})$ in SI unit. If the radius of the loop is $1 m$ ,…2022 · 27 Jul · Shift 2 · Q59 · Numerical
A metallic rod of length 20 cm is placed in North-South direction and is moved at a constant speed of 20 m/s towards East. The horizontal component of the Earth's magnetic field at that place is 4 $\times$ 10 $-$ 3 T and the angle of dip…2022 · 27 Jun · Shift 2 · Q71 · Numerical
For the given circuit the current through battery of 6 V just after closing the switch 'S' will be A. Includes diagram2022 · 28 Jul · Shift 2 · Q63 · Numerical
A coil is placed in a time varying magnetic field. If the number of turns in the coil were to be halved and the radius of wire doubled, the electrical power dissipated due to the current induced in the coil would be : (Assume the coil to…2022 · 28 Jun · Shift 2 · Q63 · MCQ
A square loop of side 20 cm and resistance 1 $Ω$ is moved towards right with a constant speed v0. The right arm of the loop is in a uniform magnetic field of 5T. The field is perpendicular to the plane of the loop and is going into… Includes diagram2021 · 1 Sep · Shift 2 · Q48 · MCQ
A conducting bar of length L is free to slide on two parallel conducting rails as shown in the figure Two resistors R1 and R2 are connected across the ends of the rails. There is a uniform magnetic field $B$ pointing into… Includes diagram2021 · 16 Mar · Shift 1 · Q60 · MCQ
The magnetic field in a region is given by $B = B_{o} (\frac{x}{a}) k$ . A square loop of side d is placed with its edges along the x and y axes. The loop is moved with a constant velocity $v$ … Includes diagram2021 · 16 Mar · Shift 2 · Q59 · MCQ
The time taken for the magnetic energy to reach 25% of its maximum value, when a solenoid of resistance R, inductance L is connected to a battery, is :2021 · 18 Mar · Shift 2 · Q54 · MCQ
The arm PQ of a rectangular conductor is moving from x = 0 to x = 2b outwards and then inwards from x = 2b to x = 0 as shown in the figure. A uniform magnetic field perpendicular to the plane is acting from x = 0 to x = b. Identify the… Includes diagram2021 · 20 Jul · Shift 1 · Q53 · MCQ
Figure shows a circuit that contains four identical resistors with resistance R = 2.0 $Ω$ , two identical inductors with inductance L = 2.0 mH and an ideal battery with emf E = 9V. The current 'i' just after the switch 'S' is closed… Includes diagram2021 · 24 Feb · Shift 2 · Q45 · MCQ
A coil of inductance 2 H having negligible resistance is connected to a source of supply whose voltage is given by V = 3t volt. (where t is in second). If the voltage is applied when t = 0, then the energy stored in the coil after 4 s is …2021 · 25 Feb · Shift 1 · Q67 · Numerical
A circular conducting coil of radius 1 m is being heated by the change of magnetic field $B$ passing perpendicular to the plane in which the coil is laid. The resistance of the coil is 2 $μ Ω$ . The magnetic field is…2021 · 25 Jul · Shift 1 · Q65 · Numerical
An inductor coil stores 64 J of magnetic field energy and dissipates energy at the rate of 640 W when a current of 8A is passed through it. If this coil is joined across an ideal battery, find the time constant of the circuit in seconds :2021 · 26 Aug · Shift 1 · Q49 · MCQ
If the maximum value of accelerating potential provided by a ratio frequency oscillator is 12 kV. The number of revolution made by a proton in a cyclotron to achieve one sixth of the speed of light is ............... [mp = 1.67 $\times$ 10…2021 · 26 Aug · Shift 2 · Q65 · Numerical
A circular coil of radius 8.0 cm and 20 turns is rotated about its vertical diameter with an angular speed of 50 rad s $-$ 1 in a uniform horizontal magnetic field of 3.0 $\times$ 10 $-$ 2 T. The maximum emf induced the coil will be…2021 · 26 Aug · Shift 2 · Q67 · Numerical
An aeroplane, with its wings spread 10 m, is flying at a speed of 180 km/h in a horizontal direction. The total intensity of earth's field at that part is 2.5 $\times$ 10 $-$ 4 Wb/m2 and the angle of dip is 60 $^{\circ}$ . The emf induced…2021 · 26 Feb · Shift 2 · Q49 · MCQ
A bar magnet is passing through a conducting loop of radius R with velocity $υ$ . The radius of the bar magnet is such that it just passes through the loop. The induced e.m.f. in the loop can be represented by the approximate curve : Includes diagram2021 · 27 Aug · Shift 1 · Q52 · MCQ
A constant magnetic field of 1T is applied in the x > 0 region. A metallic circular ring of radius 1m is moving with a constant velocity of 1 m/s along the x-axis. At t = 0s, the centre of O of the ring is at x = $-$ 1m. What will be… Includes diagram2021 · 27 Aug · Shift 2 · Q48 · MCQ
In the given figure the magnetic flux through the loop increases according to the relation $ϕ$ B(t) = 10t2 + 20t, where $ϕ$ B is in milliwebers and t is in seconds. The magnitude of current through R = 2 $Ω$ resistor at t = 5 s… Includes diagram2021 · 27 Jul · Shift 2 · Q65 · Numerical
A small square loop of side 'a' and one turn is placed inside a larger square loop of side b and one turn (b >> a). The two loops are coplanar with their centres coinciding. If a current I is passed in the square loop of side 'b',…2021 · 31 Aug · Shift 1 · Q53 · MCQ
A coil is placed in a magnetic field $B$ as shown below : A current is induced in the coil because $B$ is : Includes diagram2021 · 31 Aug · Shift 2 · Q59 · MCQ
A circular coil of radius 10 cm is placed in a uniform magnetic field of 3.0 $\times$ 10–5 T with its plane perpendicular to the field initially. It is rotated at constant angular speed about an axis along the diameter of coil and…2020 · 2 Sep · Shift 1 · Q57 · Numerical
An elliptical loop having resistance R, of semi major axis a, and semi minor axis b is placed in magnetic field as shown in the figure. If the loop is rotated about the x-axis with angular frequency $ω$ , the average power loss in the… Includes diagram2020 · 3 Sep · Shift 1 · Q54 · MCQ
A uniform magnetic field B exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field changes with time at a steady rate $\frac{d B}{d t}$ …2020 · 3 Sep · Shift 2 · Q52 · MCQ
A small bar magnet is moved through a coil at constant speed from one end to the other. Which of the following series of observations will be seen on the galvanometer G attached across the coil? Three positions shown describe : (a) the… Includes diagram2020 · 4 Sep · Shift 1 · Q53 · MCQ
Two concentric circular coils, C1 and C2 are placed in the XY plane. C1 has 500 turns, and a radius of 1 cm. C2 has 200 turns and radius of 20 cm. C2 carries a time dependent current I(t) = (5t2 – 2t + 3) A where t is in s. The emf induced…2020 · 5 Sep · Shift 1 · Q54 · Numerical
An infinitely long, straight wire carrying current I, one side opened rectangular loop and a conductor C with a sliding connector are located in the same plane, as shown, in the figure. The connector has length $l$ and resistance R. It… Includes diagram2020 · 5 Sep · Shift 2 · Q58 · MCQ
A part of a complete circuit is shown in the figure. At some instant, the value of current I is 1A and it is decreasing at a rate of 102 A s–1. The value of the potential difference VP – VQ , (in volts) at that instant, is … Includes diagram2020 · 6 Sep · Shift 1 · Q58 · Numerical
A long solenoid of radius R carries a time (t) - dependent current I(t)=I0t(1 - t). A ring of radius 2R is placed coaxially near its middle. During the time interval 0 $\leq$ t $\leq$ 1, the induced current (IR) and the induced EMF(VR) in…2020 · 7 Jan · Shift 1 · Q58 · MCQ
Consider a circular coil of wire carrying constant current I, forming a magnetic dipole. The magnetic flux through an infinite plane that contains the circular coil and excluding the circular coil area is given by $ϕ$ i. The magnetic…2020 · 7 Jan · Shift 1 · Q61 · MCQ
A loop ABCDEFA of straight edges has six corner points A(0, 0, 0), B(5, 0, 0), C(5, 5, 0), D (0, 5, 0), E(0, 5, 5) and F(0, 0, 5). The magnetic field in this region is $B = (3 i + 4 k) T$ .…2020 · 7 Jan · Shift 1 · Q63 · Numerical
A planar loop of wire rotates in a uniform magnetic field. Initially at t = 0, the plane of the loop is perpendicular to the magnetic field. If it rotates with a period of 10 s about an axis in its plane then the magnitude of induced emf…2020 · 7 Jan · Shift 2 · Q54 · MCQ
At time t = 0 magnetic field of 1000 Gauss is passing perpendicularly through the area defined by the closed loop shown in the figure. If the magnetic field reduces linearly to 500 Gauss, in the next 5s, then induced EMF in the loop is : Includes diagram2020 · 8 Jan · Shift 1 · Q57 · MCQ
A shown in the figure, a battery of emf $ε$ is connected to an inductor L and resistance R in series. The switch is closed at t = 0. The total charge that flows from the battery, between t = 0 and t = tc (tc is the time constant… Includes diagram2020 · 8 Jan · Shift 2 · Q47 · MCQ
In a fluorescent lamp choke (a small transformer) 100 V of reverse voltage is produced when the choke current changes uniformly from 0.25 A to 0 in a duration of 0.025 ms. The self-inductance of the choke (in mH) is estimated to be …2020 · 9 Jan · Shift 1 · Q43 · Numerical
A 20 Henry inductor coil is connected to a 10 ohm resistance in series as shown in figure. The time at which rate of dissipation of energy (joule's heat) across resistance is equal to the rate at which magnetic energy is stored in the… Includes diagram2019 · 8 Apr · Shift 1 · Q63 · MCQ
The total number of turns and cross-section area in a solenoid is fixed. However, its length L is varied by adjusting the separation between windings. The inductance of solenoid will be proportional to :2019 · 9 Apr · Shift 1 · Q59 · MCQ
A very long solenoid of radius R is carrying current I(t) = kte–at(k > 0), as a function of time (t $\geq$ 0). counter clockwise current is taken to be positive. A circular conducting coil of radius 2R is placed in the equatorial plane…2019 · 9 Apr · Shift 2 · Q64 · MCQ
Two coils 'P' and 'Q' are separated by some distance. When a current of 3 A flows through coil 'P', a magnetic flux of 10–3 Wb passes through 'Q'. No current is passed through 'Q'. When no current passes through 'P' and a current of 2 A…2019 · 9 Apr · Shift 2 · Q70 · MCQ
A conducting circular loop made of a thin wire, has area 3.5 $\times$ 10 $-$ 3 m2 and resistance 10 $Ω$ . It is placed perpendicular to a time dependent magnetic field B(t) = (0.4T)sin(50 $π$ t). The field is uniform in space. Then…2019 · 9 Jan · Shift 1 · Q57 · MCQ
A solid metal cube of edge length 2 cm is moving in a positive y-direction at a constant speed of 6 m/s. There is a uniform magnetic field of 0.1 T in the positive z-direction. The potential difference between the two faces of the cube…2019 · 10 Jan · Shift 1 · Q45 · MCQ
The self induced emf of a coil is 25 volts. When the current in it is changed at uniform rate from 10 A to 25 A in 1s, the change in the energy of the inductance is -2019 · 10 Jan · Shift 2 · Q68 · MCQ
There are two long co-axial solenoids of same length $l$ . The inner and outer coils have radii r1 and r2 and number of turns per unit length n1 and n2, respectively. The ratio of mutual inductance to the self - inductance of the inner-coil…2019 · 11 Jan · Shift 1 · Q60 · MCQ
A copper wire is wound on a wooden frame, whose shape is that of an equilateral triangle. If the linear dimension of each side of the frame is increased by a factor of 3, keeping the number of turns of the coil per unit length of the frame…2019 · 11 Jan · Shift 2 · Q52 · MCQ
The figure shows a square loop L of side 5 cm which is connected to a network of resistances. The whole setup is moving towards right with a constant speed of 1 cm s-1. At some instant, a part of L is in a uniform magnetic field of 1 T,… Includes diagram2019 · 12 Apr · Shift 1 · Q52 · MCQ
A 10 m long horizontal wire extends from North East to South West. It is falling with a speed of 5.0 ms–1, at right angles to the horizontal component of the earth's magnetic field of 0.3 $\times$ 10–4 Wb/m2. The value of the induced emf…2019 · 12 Jan · Shift 2 · Q50 · MCQ
At the center of a fixed large circular coil of radius R, a much smaller circular coil of radius r is placed. The two coils are concentric and are in the same plane. The larger coil carries a current I. The smaller coil is set to rotate…2018 · 15 Apr · Shift 2 · Q47 · MCQ
A copper rod of mass m slides under gravity on two smooth parallel rails, with separation l and set at an angle of $θ$ with the horizontal. At the bottom rails are joined by a resistance R. There is a uniform magnetic field B normal… Includes diagram2018 · 15 Apr · Shift 2 · Q51 · MCQ
A coil of cross-sectional area A having n turns is placed in a uniform magnetic field B. When it is rotated with an angular velocity $ω,$ the maxium e.m.f. induced in the coil will be:2018 · 16 Apr · Shift 1 · Q54 · MCQ
A small circular loop of wire of radius a is located at the centre of a much larger circular wire loop of radius b. The two loops are in the same plane. The outer loop of radius b carries an alternating current I = Io cos ( $ω$ t). The…2017 · 8 Apr · Shift 1 · Q54 · MCQ
A uniform magnetic field B of 0.3 T is along the positive Z-direction. A rectangular loop (abcd) of sides 10 cm × 5 cm carries a current I of 12 A. Out of the following different orientations which one corresponds to stable equilibrium ?2017 · 9 Apr · Shift 1 · Q68 · MCQ
In a coil of resistance 100 $Ω$ , a current is induced by changing the magnetic flux through it as shown in the figure. The magnitude of change in flux through the coil is: Includes diagram2017 · Shift 0 · Q47 · MCQ
A conducting metal circular-wire-loop of radius r is placed perpendicular to a magnetic field which varies with time as B = B0e $^{\frac{- t}{r}}$ , where B0 and $τ$ are constants, at time t = 0. If the resistance of the loop is R…2016 · 10 Apr · Shift 1 · Q54 · MCQ
Consider a thin metallic sheet perpendicular to the plane of the paper moving with speed ‘v’ in a uniform magnetic field B going into the plane of the paper (See figure). If charge densities $σ$ 1 and $σ$ 2 are induced on the… Includes diagram2016 · 10 Apr · Shift 1 · Q65 · MCQ
Two coaxial solenoids of different radius carry current $I$ in the same direction. $F_{1}$ be the magnetic force on the inner solenoid due to the outer one and $F_{2}$ be the magnetic force on the outer…2015 · Shift 0 · Q50 · MCQ
A metallic rod of length $^{'} ℓ^{'}$ is tied to a string of length $2 ℓ$ and made to rotate with angular speed $w$ on a horizontal table with one end of the string fixed. If there is a vertical magnetic field $^{'} B^{'}$ in the region, the $e . m . f$ … Includes diagram2013 · Shift 0 · Q57 · MCQ
A circular loop of radius $0.3 c m$ lies center of the small loop is on the axis of the bigger loop. The distance between their centers is $15 c m .$ If a current of $2.0 A$ flows through the smaller loop, than the flux linked with bigger loop is2013 · Shift 0 · Q59 · MCQ
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…2012 · Shift 0 · Q52 · MCQ
A boat is moving due east in a region where the earth's magnetic fields is $5.0 \times 1 0^{- 5} N A^{- 1} m^{- 1}$ due north and horizontal. The best carries a vertical aerial $2 m$ long. If the speed of the boat is $1.50 m s^{- 1},$ …2011 · Shift 0 · Q59 · MCQ
A rectangular loop has a sliding connector $P Q$ of length $l$ and resistance $R Ω$ 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 $I_{1}, I_{2}$ … Includes diagram2010 · Shift 0 · Q57 · MCQ
Two coaxial solenoids are made by winding thin insulated wire over a pipe of cross-sectional area $A = 10 c m^{2}$ and length $= 20 c m$ . If one of the solenoid has $300$ turns and the other $400$ turns, their mutual inductance is $(μ_{0} = 4 π \times 10^{- 7} T m A^{- 1})$ …2008 · Shift 0 · Q63 · MCQ
An ideal coil of $10 H$ is connected in series with a resistance of $5Ω$ and a battery of $5 V$ . $2$ second after the connection is made, the current flowing in ampere in the circuit is2007 · Shift 0 · Q70 · MCQ
An inductor $(L = 100 m H)$ , a resistor $(R = 100 Ω)$ and a battery $(E = 100 V)$ are initially connected in series as shown in the figure. After a long time the battery is disconnected after short… Includes diagram2006 · Shift 0 · Q88 · MCQ
Which of the following units denotes the dimension $\frac{M L ^{2}}{Q ^{2}}$ , where $Q$ denotes the electric charge?2006 · Shift 0 · Q92 · MCQ
The flux linked with a coil at any instant $^{'} t^{'}$ is given by $ϕ = 10 t^{2} - 50 t + 250$ The induced $e m f$ at $t = 3 s$ is2006 · Shift 0 · Q95 · MCQ
A coil of inductance $300 m H$ and resistance $2 Ω$ is connected to a source of voltage $2 V$ . The current reaches half of its steady state value in2005 · Shift 0 · Q130 · MCQ
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… Includes diagram2005 · Shift 0 · Q138 · MCQ
A coil having $n$ turns and resistance $R Ω$ is connected with a galvanometer of resistance $4 R Ω.$ This combination is moved in time $t$ seconds from a magnetic field $W_{1}$ weber to $W_{2}$ weber. The induced current in the…2004 · Shift 0 · Q149 · MCQ
In a uniform magnetic field of induction $B$ a wire in the form of a semicircle of radius $r$ rotates about the diameter of the circle with an angular frequency $ω .$ The axis of rotation is perpendicular to the field. If the total…2004 · Shift 0 · Q150 · MCQ
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 $0.2 \times 1 0^{- 4} T,$ then the $e . m . f .$ developed between…2004 · Shift 0 · Q151 · MCQ
When the current changes from $+ 2 A$ to $- 2 A$ in $0.05$ second, an $e . m . f .$ of $8 V$ is inducted in a coil. The coefficient of self- induction of the coil is2003 · Shift 0 · Q125 · MCQ
Two coils are placed close to each other. The mutual inductance of the pair of coils depends upon2003 · Shift 0 · Q136 · MCQ
The inductance between $A$ and $D$ is Includes diagram2002 · Shift 0 · Q133 · MCQ
A conducting square loop of side $L$ and resistance $R$ moves in its plane with a uniform velocity $v$ perpendicular to one of its sides. A magnetic induction $B$ constant in time and space, pointing perpendicular and into the plane at the… Includes diagram2002 · Shift 0 · Q134 · MCQ