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Physics · Magnetism and Matter

JEE Main 2025 — 7 April, Morning Shift — Question 64

The percentage increase in magnetic field (B) when space within a current carrying solenoid is filled with magnesium (magnetic susceptibility χMg=1.2×10−5\chi \mathrm{Mg}=1.2 \times 10^{-5} ) is

  1. Option A:

    65×10−3%\frac{6}{5} \times 10^{-3} \%

    Correct
  2. Option B:

    53×10−5%\frac{5}{3} \times 10^{-5} \%

  3. Option C:

    56×10−5%\frac{5}{6} \times 10^{-5} \%

  4. Option D:

    56×10−4%\frac{5}{6} \times 10^{-4} \%

Answer: A

Step-by-step solution

ΔBB=(1+xB)B−BB=xB\frac{\Delta B}{B}=\frac{\left(1+x_{B}\right) B-B}{B}=x_{B}

So percentage increase =(xB×100)=\left(x_{B} \times 100\right)

=1.2×10−5×100=65×10−3\begin{aligned} & =1.2 \times 10^{-5} \times 100 & =\frac{6}{5} \times 10^{-3} \end{aligned}

Answer key and solution verified before publishing.

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Exam
JEE Main 2025
Paper
7 April, Morning Shift
Subject
Physics
Chapter
Magnetism and Matter
Topic
Magnetization and Magnetic Intensity, Hysteresis
The percentage increase in magnetic field (B) when space within a… | JEE Main 2025 PYQ with Solution · DhiX AI