Advertisements
Advertisements
प्रश्न
A proton has spin and magnetic moment just like an electron. Why then its effect is neglected in magnetism of materials?
उत्तर
Spinning of a proton is negligible as compared to that of electron spin because its mass is very larger than the mass of an electron.
The comparison between the spinning of a proton and an electron can be done by comparing their magnetic dipole moment which can be given by
As we know that magnetic moment of a charged particle of charge e and mass m is Me = `(eh)/(4πme)` and Mp = `(eh)/(4πm p)`
As charge on proton and electron are equal in magnitude so
`M oo 1/m` or `M_e/M_p = m_p/m_e`
As the mass of proton is 1836 times as of electron, so magnetic moment of proton
`M_p = M_e/m_p m_e = (M_e * m_e)/(1836 m_e)`, `M_p = 1/1836` of `M_e`
So magnetic moment of proton is `1/1836` times of electron, so can be neglected.
APPEARS IN
संबंधित प्रश्न
An electron moves along +x direction. It enters into a region of uniform magnetic field. `vecB` directed along –z direction as shown in fig. Draw the shape of the trajectory followed by the electron after entering the field.
Solve the following problem.
A magnetic pole of a bar magnet with a pole strength of 100 A m is 20 cm away from the centre of a bar magnet. The bar magnet has a pole strength of 200 A m and has a length of 5 cm. If the magnetic pole is on the axis of the bar magnet, find the force on the magnetic pole.
Four point masses, each of value m, are placed at the comers of a square ABCD of side L, the moment of inertia of this system about an axis through A and parallel to BD is ______.
The resistance of ideal voltmeter is
A magnetic needle suspended freely orients itself:-
A toroid of n turns, mean radius R and cross-sectional radius a carries current I. It is placed on a horizontal table taken as x-y plane. Its magnetic moment m ______.
Suppose we want to verify the analogy between electrostatic and magnetostatic by an explicit experiment. Consider the motion of (i) electric dipole p in an electrostatic field E and (ii) magnetic dipole m in a magnetic field B. Write down a set of conditions on E, B, p, m so that the two motions are verified to be identical. (Assume identical initial conditions.)
Use (i) the Ampere’s law for H and (ii) continuity of lines of B, to conclude that inside a bar magnet, (a) lines of H run from the N pole to S pole, while (b) lines of B must run from the S pole to N pole.
