Magnetic Effects of Current & Magnetism · JEE Main previous year questions

2024 35 questions

1. Q382024 · 9 Apr 2024 · Shift 1

   Given below are two statements : Statement (I) : When currents vary with time, Newton's third law is valid only if momentum carried by the electromagnetic field is taken into account Statement (II) : Ampere's circuital law does not depend on Biot-Savart's law. In the light of the above statements, choose the correct answer from the options given below :

   1. A.Both Statement I and Statement II are false
   2. B.Statement I is false but Statement II is true
   3. C.Both Statement I and Statement II are true
   4. D.Statement I is true but Statement II is false
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   Answer: D

2. Q512024 · 9 Apr 2024 · Shift 1· Numerical answer

   A square loop of edge length $2\text{ m}$ carrying current of $2\text{ A}$ is placed with its edges parallel to the $x$-$y$ axis. A magnetic field is passing through the $x$-$y$ plane and expressed as $\vec{B}=B_0(1+4x)\hat{k}$, where $B_0=5\text{ T}$. The net magnetic force experienced by the loop is ______ $\text{N}$.

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   Answer: 160

3. Q432024 · 9 Apr 2024 · Shift 2

   A proton and a deuteron ($q=+\mathrm{e},m=2.0\mathrm{u}$) having same kinetic energies enter a region of uniform magnetic field $\vec{B}$, moving perpendicular to $\vec{B}$. The ratio of the radius $r_d$ of deuteron path to the radius $r_p$ of the proton path is:

   1. A.$1:2$
   2. B.$1:1$
   3. C.$\sqrt{2}:1$
   4. D.$1:\sqrt{2}$
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   Answer: C

4. Q482024 · 9 Apr 2024 · Shift 2
   
   1. A.zero
   2. B.$4.5\mathrm{mV}$
   3. C.$0.3\mathrm{mV}$
   4. D.$3\mathrm{mV}$
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   Answer: A

5. Q582024 · 9 Apr 2024 · Shift 2· Numerical answer

   A straight magnetic strip has a magnetic moment of $44{\mathrm{Am}}^2$. If the strip is bent in a semicircular shape, its magnetic moment will be ____ ${\mathrm{Am}}^2$. (given $\pi =\frac{22}{7}$)

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   Answer: 28

6. Q412024 · 8 Apr 2024 · Shift 1

   Paramagnetic substances: A. align themselves along the directions of external magnetic field. B. attract strongly towards external magnetic field. C. has susceptibility little more than zero. D. move from a region of strong magnetic field to weak magnetic field. Choose the most appropriate answer from the options given below:

   1. A.A, B, C Only
   2. B.A, C Only
   3. C.A, B, C, D
   4. D.B, D Only
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   Answer: B

7. Q312024 · 8 Apr 2024 · Shift 2

   A long straight wire of radius $a$ carries a steady current $\mathrm{I}$. The current is uniformly distributed across its cross section. The ratio of the magnetic field at $\frac{a}{2}$ and $2a$ from axis of the wire is :

   1. A.$4:1$
   2. B.$3:4$
   3. C.$1:1$
   4. D.$1:4$
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   Answer: C

8. Q592024 · 8 Apr 2024 · Shift 2· Numerical answer

   The coercivity of a magnet is $5\times 10^{3}A/m$. The amount of current required to be passed in a solenoid of length $30\mathrm{cm}$ and the number of turns $150$, so that the magnet gets demagnetised when inside the solenoid is ____ $\mathrm{A}$.

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   Answer: 10

9. Q412024 · 6 Apr 2024 · Shift 2
   
   1. A.(A)-(III), (B)-(IV), (C)- (I), (D)-(II)
   2. B.(A)-(III), (B)-(I), (C)-(IV), (D)-(II)
   3. C.(A)-(IV), (B)-(I), (C)-(III), (D)-(II)
   4. D.(A)-(I), (B)-(III), (C)-(II), (D)-(IV)
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   Answer: B

10. Q542024 · 6 Apr 2024 · Shift 2· Numerical answer

    A coil having 100 turns, area of $5\times 10^{-3}{\text{ m}}^2$, carrying current of $1\text{ mA}$ is placed in uniform magnetic field of $0.20\text{ T}$ such a way that plane of coil is perpendicular to the magnetic field. The work done in turning the coil through $90^{\circ }$ is ________ $\mu \text{J}$.

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    Answer: 100

11. Q602024 · 5 Apr 2024 · Shift 2· Numerical answer

    A solenoid of length $0.5\mathrm{m}$ has a radius of $1\mathrm{cm}$ and is made up of '$\mathrm{m}$' number of turns. It carries a current of $5\mathrm{A}$. If the magnitude of the magnetic field inside the solenoid is $6.28\times 10^{-3}\mathrm{T}$ then the value of $\mathrm{m}$ is ____.

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    Answer: 500

12. Q322024 · 4 Apr 2024 · Shift 1

    An electron is projected with uniform velocity along the axis inside a current carrying long solenoid. Then :

    1. A.the electron will experience a force at $45^{\circ }$ to the axis and execute a helical path.
    2. B.the electron will be accelerated along the axis.
    3. C.the electron path will be circular about the axis.
    4. D.the electron will continue to move with uniform velocity along the axis of the solenoid.
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    Answer: D

13. Q562024 · 4 Apr 2024 · Shift 1· Numerical answer
    
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    Answer: 50

14. Q362024 · 4 Apr 2024 · Shift 2

    The magnetic moment of a bar magnet is $0.5{\text{ Am}}^2$. It is suspended in a uniform magnetic field of $8\times 10^{-2}\text{ T}$. The work done in rotating it from its most stable to most unstable position is:

    1. A.$4\times 10^{-2}\text{ J}$
    2. B.$16\times 10^{-2}\text{ J}$
    3. C.$8\times 10^{-2}\text{ J}$
    4. D.$\text{Zero}$
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    Answer: C

15. Q522024 · 4 Apr 2024 · Shift 2· Numerical answer
    
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    Answer: 5

16. Q562024 · 1 Feb 2024 · Shift 1· Numerical answer

    A regular polygon of 6 sides is formed by bending a wire of length $4\pi$ meter. If an electric current of $4\pi \sqrt{3}$ A is flowing through the sides of the polygon, the magnetic field at the centre of the polygon would be $x\times 10^{-7}\mathrm{T}$. The value of $x$ is ____.

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    Answer: 72

17. Q452024 · 1 Feb 2024 · Shift 2

    If frequency of electromagnetic wave is $60\text{ MHz}$ and it travels in air along $z$ direction then the corresponding electric and magnetic field vectors will be mutually perpendicular to each other and the wavelength of the wave (in $\text{m}$ ) is :

    1. A.2.5
    2. B.5
    3. C.10
    4. D.2
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    Answer: B

18. Q552024 · 1 Feb 2024 · Shift 2· Numerical answer

    A moving coil galvanometer has 100 turns and each turn has an area of $2.0{\text{ cm}}^2$. The magnetic field produced by the magnet is $0.01\text{ T}$ and the deflection in the coil is $0.05\text{ radian}$ when a current of $10\text{ mA}$ is passed through it. The torsional constant of the suspension wire is $x\times 10^{-5}\text{ N}-\text{m/rad}$. The value of $x$ is ________ .

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    Answer: 4

19. Q582024 · 1 Feb 2024 · Shift 2· Numerical answer

    A coil of 200 turns and area $0.20{\text{ m}}^2$ is rotated at half a revolution per second and is placed in uniform magnetic field of $0.01\text{ T}$ perpendicular to axis of rotation of the coil. The maximum voltage generated in the coil is $\frac{2\pi }{\beta }\text{ volt}$. The value of $\beta$ is ________ .

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    Answer: 5

20. Q382024 · 31 Jan 2024 · Shift 1
    
    1. A.$iBR\hat{j}$
    2. B.$-2iBR\hat{j}$
    3. C.$2iBR\hat{j}$
    4. D.$-iBR\hat{j}$
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    Answer: B

21. Q432024 · 31 Jan 2024 · Shift 1

    A coil is placed perpendicular to a magnetic field of $5000\mathrm{T}$. When the field is changed to $3000\mathrm{T}$ in $2\mathrm{s}$, an induced emf of $22\mathrm{V}$ is produced in the coil. If the diameter of the coil is $0.02\mathrm{m}$, then the number of turns in the coil is:

    1. A.35
    2. B.70
    3. C.7
    4. D.140
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    Answer: B

22. Q522024 · 31 Jan 2024 · Shift 1· Numerical answer

    An electron moves through a uniform magnetic field $\vec{B}=B_0\hat{i}+2B_0\hat{j}T$. At a particular instant of time, the velocity of electron is $\vec{u}=3\hat{i}+5\hat{j}m/s$. If the magnetic force acting on electron is $\vec{F}=5e\hat{k}N$, where $e$ is the charge of electron, then the value of $B_0$ is ____ $T$.

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    Answer: 5

23. Q312024 · 31 Jan 2024 · Shift 2

    Given below are two statements: Statement I: Electromagnetic waves carry energy as they travel through space and this energy is equally shared by the electric and magnetic fields. Statement II: When electromagnetic waves strike a surface, a pressure is exerted on the surface. In the light of the above statements, choose the most appropriate answer from the options given below:

    1. A.Statement I is incorrect but Statement II is correct.
    2. B.Both Statement I and Statement II are correct.
    3. C.Statement I is correct but Statement II is incorrect.
    4. D.Both Statement I and Statement II are incorrect.
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    Answer: B

24. Q542024 · 31 Jan 2024 · Shift 2· Numerical answer

    Two circular coils $P$ and $Q$ of 100 turns each have same radius of $\pi \mathrm{cm}$. The currents in $P$ and $Q$ are $1A$ and $2A$ respectively. $P$ and $Q$ are placed with their planes mutually perpendicular with their centers coincide. The resultant magnetic field induction at the center of the coils is $\sqrt{x}mT$, where $x=$ ____. [Use ${\mu }_0=4\pi \times 10^{-7}\mathrm{Tm}{\mathrm{A}}^{-1}$]

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    Answer: 20

25. Q512024 · 30 Jan 2024 · Shift 1· Numerical answer

    The horizontal component of earth's magnetic field at a place is $3.5\times 10^{-5}\text{ T}$. A very long straight conductor carrying current of $\sqrt{2}\text{ A}$ in the direction from South east to North West is placed. The force per unit length experienced by the conductor is _________ $\times 10^{-6}\text{ N/m}$.

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    Answer: 35