Maharashtra Board Solutions for Chapter: Magnetic Materials, Exercise 6: Exercises

A rectangular magnet suspended freely has a period of oscillation equal to T. Now it is broken into two equal halves ( each having half of the original length) and one piece is made to oscillate freely. Its period of oscillation is T', the ratio of T' / T is. 

A magnetising field of $360 {\mathrm{Am}}^{-1}$ produces a magnetic flux density $\left(\mathrm{B}\right)=0.6 \mathrm{T}$ in a ferromagnetic material. What is its permeability in $\mathrm{Tm} {\mathrm{A}}^{-1}$ ?

A paramagnetic gas has $2.0\times {10}^{26}$ atoms/m³ with atomic magnetic dipole moment of $1.5\times {10}^{-23}{\mathrm{Am}}^2$ each. The gas is at $27° \mathrm{C}$. Find the maximum magnetization intensity of this sample.

A paramagnetic gas has $2.0\times {10}^{26}$ atoms/m³ with atomic magnetic dipole moment of $1.5\times {10}^{-23}{\mathrm{Am}}^2$ each. The gas is at $27° \mathrm{C}$. If the gas in this problem is kept in a uniform magnetic field of $3 \mathrm{T}$, is it possible to achieve saturation magnetization? Why? ${\mathrm{k}}_{\mathrm{B}}=1.38\times {10}^{-23}{\mathrm{JK}}^{-1}$.

A magnetic needle placed in uniform magnetic field has magnetic moment of $2\times {10}^{-2}{\mathrm{Am}}^2$, and moment of inertia of $7.2\times {10}^{-7}{\mathrm{kgm}}^2$. It performs $10$ complete oscillations in $6 \mathrm{s}$. What is the magnitude of the magnetic field ? 

A short bar magnet is placed in an external magnetic field of $700 \mathrm{gauss}$. When its axis makes an angle of $30°$ with the external magnetic field, it experiences a torque of $0.014 \mathrm{Nm}$. Find the magnetic moment of the magnet, and the work done in moving it from its most stable to most unstable position.

A magnetic needle is suspended freely so that it can rotate freely in the magnetic meridian. In order to keep it in the horizontal position, a weight of $0.1 \mathrm{g}$ is kept on one end of the needle. If the pole strength of this needle is $20 \mathrm{Am}$, find the value of the vertical component of the earth's magnetic field. $\left(\mathrm{g}=9.8{\mathrm{ms}}^{-2}\right)$

The susceptibility of a paramagnetic material is $\mathrm{\chi }$ at $27° \mathrm{C}$. At what temperature its susceptibility be $\mathrm{\chi }/3$ ?