Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main
Exam
JEE Main
Subject
Physics
Chapter
Magnetic Properties of Matter

JEE Main · Physics · Magnetic Properties of Matter

Two short bar magnets have their magnetic moments 1.2 Am^2 and 1.0...

Two short bar magnets have their magnetic moments 1.2Am21.2 \mathrm{Am}^2 and 1.0Am21.0 \mathrm{Am}^2. They are placed on a horizontal table parallel to each other at a distance of 20 cm20 \mathrm{~cm} between their centres, such that their north poles pointing towards geographic south. They have common magnetic equatorial line. Horizontal component of earth's field is 3.6×10−5 T3.6 \times 10^{-5} \mathrm{~T}. Then, the resultant horizontal magnetic induction at mid point of the line joining their centers is (μ04π=10−7 N/m)\left(\frac{\mu_0}{4 \pi}=10^{-7} \mathrm{~N} / \mathrm{m}\right)

Options

  1. A3.6×10−5 T3.6 \times 10^{-5} \mathrm{~T}
  2. B1.84×10−4 T1.84 \times 10^{-4} \mathrm{~T}
  3. C2.56×10−4 T2.56 \times 10^{-4} \mathrm{~T}
  4. D5.8×10−5 T5.8 \times 10^{-5} \mathrm{~T}

Correct answer

C. 2.56×10−4 T2.56 \times 10^{-4} \mathrm{~T}

Step-by-step solution

We knows, B=μ04πMr3B=\frac{\mu_0}{4 \pi} \frac{M}{r^3} Hence the resultant horizontal magnetic induction point of the line joining their conters is B=B1+B2+BH=10−7×1.2(10×10−2)3+10−7×1(10×10−2)3+3.6×10−5=1.2×10−4+1×10−4+0.36×10−4=2.56×10−4 T\begin{aligned} B & =B_1+B_2+B_H \\ & =\frac{10^{-7} \times 1.2}{\left(10 \times 10^{-2}\right)^3}+\frac{10^{-7} \times 1}{\left(10 \times 10^{-2}\right)^3}+3.6 \times 10^{-5} \\ & =1.2 \times 10^{-4}+1 \times 10^{-4}+0.36 \times 10^{-4} \\ & =2.56 \times 10^{-4} \mathrm{~T} \end{aligned}
Practice Magnetic Properties of Matter on Quantrex Academy →

More from Magnetic Properties of Matter

A solenoid has a core made of material with relative permeability 400 . The magnetic… JEE Main 2026Two identical small bar magnets each of dipole moment 3 5 J/T are placed at a center to… JEE Main 2026Given below are two statements: one is labelled as Assertion (A) and the other is… JEE Main 2026Given below are two statements : one is labelled as Assertion (A) and the other is… JEE Main 2025The percentage increase in magnetic field (B) when space within a current carrying… JEE Main 2025A solenoid having area A and length ' l ' is filled with a material having relative… JEE Main 2025The relationship between the magnetic susceptibility (χ) and the magnetic permeability… JEE Main 2025A bar magnet has total length 2 l=20 units and the field point P is at a distance d=10… JEE Main 2025 Full Magnetic Properties of Matter list All 99 Percentile Qs Bank for JEE Main PYQs