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Friday, 9 October

JEE Main 2025 · PhysicsMultiple choiceSingle correctMediumCalculation

JEE Main 7 April 2025, Shift 1, Physics Q39

Question 39 of 75 in this shift, Physics question 14 of 25, Section A.

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_{Mg} = 1.2 \times 10^{-5}) is :
  1. (1)53×10−5%\frac{5}{3} \times 10^{-5}\%
  2. (2)65×10−3%\frac{6}{5} \times 10^{-3}\%Official answer
  3. (3)56×10−5%\frac{5}{6} \times 10^{-5}\%
  4. (4)56×10−4%\frac{5}{6} \times 10^{-4}\%

Official answer

Option 2

NTA final key.

Chapter
Magnetism and Matter
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.