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

2022 31 questions

1. Q402022 · 25 Jun 2022 · Shift 1

   A long straight wire with a circular cross-section having radius $\mathrm{R}$, is carrying a steady current $\mathrm{I}$. The current $\mathrm{I}$ is uniformly distributed across this cross-section. Then the variation of magnetic field due to current $\mathrm{I}$ with distance $r$ ($r<\mathrm{R}$) from its centre will be :

   1. A.$B\propto r^2$
   2. B.$B\propto r$
   3. C.$B\propto \frac{1}{r^2}$
   4. D.$B\propto \frac{1}{r}$
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   Answer: B

2. Q402022 · 25 Jun 2022 · Shift 2

   Given below are two statements : Statement I : Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature. Statement II : Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field. Choose the correct answer from the options given below :

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

3. Q412022 · 25 Jun 2022 · Shift 2

   A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of magnetic field will be equal to

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

4. Q382022 · 24 Jun 2022 · Shift 2

   A proton, a deuteron and an $\alpha$-particle with same kinetic energy enter into a uniform magnetic field at right angle to magnetic field. The ratio of the radii of their respective circular paths is :

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

5. Q462022 · 24 Jun 2022 · Shift 2

   An electric bulb is rated as $200\mathrm{W}$. What will be the peak magnetic field at $4\mathrm{m}$ distance produced by the radiations coming from this bulb? Consider this bulb as a point source with $3.5\%$ efficiency.

   1. A.$1.19\times 10^{-8}\mathrm{T}$
   2. B.$1.71\times 10^{-8}\mathrm{T}$
   3. C.$0.84\times 10^{-8}\mathrm{T}$
   4. D.$3.36\times 10^{-8}\mathrm{T}$
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   Answer: B

6. Q552022 · 24 Jun 2022 · Shift 2· Numerical answer

   A circular coil of 1000 turns each with area $1{\mathrm{m}}^2$ is rotated about its vertical diameter at the rate of one revolution per second in a uniform horizontal magnetic field of $0.07\mathrm{T}$. The maximum voltage generation will be ____ $\mathrm{V}$.

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   Answer: 440