Advertisements
Advertisements
Question
A proton has spin and magnetic moment just like an electron. Why then its effect is neglected in magnetism of materials?
Advertisements
Solution
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
RELATED QUESTIONS
Magnetic lines of force are closed continuous curves.
Write any three properties of magnetic lines of force.
A bar magnet of length 1 cm and cross-sectional area 1.0 cm2 produces a magnetic field of 1.5 × 10−4 T at a point in end-on position at a distance 15 cm away from the centre. (a) Find the magnetic moment M of the magnet. (b) Find the magnetisation I of the magnet. (c) Find the magnetic field B at the centre of the magnet.
An electron moves along +x direction. It enters into a region of uniform magnetic field `vec B` directed along −z direction as shown in fig. Draw the shape of the trajectory followed by the electron after entering the field.
Choose the correct option.
Inside a bar magnet, the magnetic field lines
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.
Answer the following question in detail.
A circular magnet is made with its north pole at the centre, separated from the surrounding circular south pole by an air gap. Draw the magnetic field lines in the gap.
Which of the following statement about magnetic field lines is true?
In which case of comparing solenoid and bar magnet there is no exact similarity?
Magnetic field at far axial point due to solenoid as well as bar magnet varies ______.
When current is double deflection is also doubled in
A magnetic needle suspended freely orients itself:-
A bar magnet of magnetic moment 3.0 Am is placed in a uniform magnetic field of 2 × 10-5T. If each pole of the magnet experience a force of 6 × 10-4 N, the length of the magnet is ______.
Magnetic dipole moment is a ______
A bar magnet of magnetic moment m and moment of inertia I (about centre, perpendicular to length) is cut into two equal pieces, perpendicular to length. Let T be the period of oscillations of the original magnet about an axis through the midpoint, perpendicular to length, in a magnetic field B. What would be the similar period T′ for each piece?
