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

2024 35 questions

1. Q602024 · 30 Jan 2024 · Shift 1· Numerical answer

   A ceiling fan having 3 blades of length $80\text{ cm}$ each is rotating with an angular velocity of $1200\text{ rpm}$. The magnetic field of earth in that region is $0.5\text{G}$ and angle of dip is $30^{\circ }$. The emf induced across the blades is $\mathrm{N}\pi \times 10^{-5}\text{ V}$. The value of N is _________.

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   Answer: 32

2. Q562024 · 29 Jan 2024 · Shift 1· Numerical answer

   The magnetic potential due to a magnetic dipole at a point on its axis situated at a distance of $20\text{ cm}$ from its center is $1.5\times 10^{-5}\text{ T m}$. The magnetic moment of the dipole is _______ ${\text{A m}}^2$. (Given : $\frac{{\mu }_o}{4\pi }=10^{-7}{\text{TmA}}^{-1}$ )

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   Answer: 6

3. Q422024 · 29 Jan 2024 · Shift 2

   A plane electromagnetic wave of frequency $35\text{ MHz}$ travels in free space along the $X$-direction. At a particular point (in space and time) $\vec{E}=9.6\hat{j}\text{ V/m}$. The value of magnetic field at this point is :

   1. A.$9.6\hat{j}T$
   2. B.$3.2\times 10^{-8}\hat{i}T$
   3. C.$9.6\times 10^{-8}\hat{k}T$
   4. D.$3.2\times 10^{-8}\hat{k}T$
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   Answer: D

4. Q502024 · 29 Jan 2024 · Shift 2

   Two particles $X$ and $Y$ having equal charges are being accelerated through the same potential difference. Thereafter they enter normally in a region of uniform magnetic field and describe circular paths of radii $R_1$ and $R_2$ respectively. The mass ratio of $X$ and $Y$ is :

   1. A.$\left(\frac{R_1}{R_2}\right)$
   2. B.$\left(\frac{R_2}{R_1}\right)$
   3. C.${\left(\frac{R_2}{R_1}\right)}^2$
   4. D.${\left(\frac{R_1}{R_2}\right)}^2$
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   Answer: D

5. Q592024 · 29 Jan 2024 · Shift 2· Numerical answer

   A charge of $4.0\mu \mathrm{C}$ is moving with a velocity of $4.0\times 10^6{\text{ ms}}^{-1}$ along the positive $y$ axis under a magnetic field $\vec{B}$ of strength $(2\hat{k})\text{T}$. The force acting on the charge is $x\hat{i}N$. The value of $x$ is _________.

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   Answer: 32

6. Q602024 · 29 Jan 2024 · Shift 2· Numerical answer

   A horizontal straight wire $5\text{ m}$ long extending from east to west is falling freely at right angle to horizontal component of earths magnetic field $0.60\times 10^{-4}{\text{ Wbm}}^{-2}$. The instantaneous value of emf induced in the wire when its velocity is $10{\text{ ms}}^{-1}$ is _________ $\times 10^{-3}\text{ V}$.

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   Answer: 3

7. Q342024 · 27 Jan 2024 · Shift 1

   A proton moving with a constant velocity passes through a region of space without any change in its velocity. If $\vec{\text{E}}$ and $\vec{\text{B}}$ represent the electric and magnetic fields respectively, then the region of space may have : (A) $\text{E}=0$, $\text{B}=0$ (B) $\text{E}=0$, $\text{B}\ne 0$ (C) $\text{E}\ne 0$, $\text{B}=0$ (D) $\text{E}\ne 0$, $\text{B}\ne 0$ Choose the most appropriate answer from the options given below :

   1. A.(A), (B) and (C) only
   2. B.(A), (C) and (D) only
   3. C.(A), (B) and (D) only
   4. D.(B), (C) and (D) only
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   Answer: C

8. Q422024 · 27 Jan 2024 · Shift 1

   A rectangular loop of length $2.5\text{ m}$ and width $2\text{ m}$ is placed at $60^{\circ }$ to a magnetic field of $4\text{ T}$. The loop is removed from the field in $10\text{ sec}$. The average emf induced in the loop during this time is

   1. A.$-2\text{ V}$
   2. B.$+2\text{ V}$
   3. C.$+1\text{ V}$
   4. D.$-1\text{ V}$
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   Answer: C

9. Q582024 · 27 Jan 2024 · Shift 1· Numerical answer
   
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   Answer: 160

10. Q572024 · 27 Jan 2024 · Shift 2· Numerical answer
    
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    Answer: 3