Q. A rod of ferromagnetic material with dimensions $10\ cm \times 0.5\ cm \times 0.2\ cm$ is placed in a magnetic field of strength $0.5 \times 10^{4}A - m^{- 1}$ as a result of which of which a magnetic moment of 0.5 $A - m^{- 2}$ is produced in rod. The value of magnetic induction will be
A) 0.54 T
B) 6.28 T
C) 0.358 T
D) 2.591 T
Explanation
(b) Here,$\ V = (10 \times 0.5 \times 0.2)cm^{3}$
$= 1\ cm^{3} = 10^{- 6}m^{3}$
$H = 0.5 \times 10^{4}\ Am^{- 1},\ M = 5\ Am^{2},B = ?$
$\ I = \frac{M}{V} = \frac{5}{10^{- 6}} = 5 \times 10^{6}$ Am
From $B = \mu_{0}(I/\text{+}H$)
$B = 4\pi \times 10^{- 7}\left( 5 \times 10^{6} + 0.5 \times 10^{4} \right) =$6.28 T
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.