91Ó°ÊÓ

A monoenergetic (18 keV) electron beam initially in the horizontal direction is subjected to a horizontal magnetic field of \(0.04\) G normal to the initial direction. Estimate the up or down deflection of the beam over a distance of \(30 \mathrm{~cm}\left(m_{e}=9.11 \times 10^{31} \mathrm{~kg}\right) .\) [Note: Data in this exercise are so chosen that the answer will give you an idea of the effect of earth from the electron gun to the screen in a TV set.]

A sample of paramagnetic salt contains \(2.0 \times 10^{24}\) atomic dipoles each of dipole moment \(1.5 * 10 \quad J T\). The sample is placed under a homogeneous magnetic field of \(0.64 \mathrm{~T}\), and cooled to a temperature of \(4.2 \mathrm{~K}\). The degree of magnetic saturation achieved is equal to \(15 \%\). What is the total dipole moment of the sample for a magnetic field of \(0.98 \mathrm{~T}\) and a temperature of \(2.8 \mathrm{~K} ?\) (Assume Curie

A Rowland ring of mean radius \(15 \mathrm{~cm}\) has 3500 turns of wire wound on a ferromagnetic core of relative permeability 800. What is the magnetic field B in the core for a magnetising current of \(1.2\) A?

The magnetic moment vectors \(\mu_{s}\) and \(\mu_{1}\) associated with the intrinsic spin angular momentum \(\mathbf{S}\) and orbital angular momentum \(\mathbf{I}_{t}\) respectively, of an electron are predicted by quantum theory (and verified experimentally to a high accuracy) to be given by: \(\mu_{s}=e / m\) ) \(\mathbf{S}\) \(\left.\mu_{I}=e / 2 m\right) I\) Which of these relations is in accordance with the result expected classically? Outline the derivation of the classical result.