The magnetic moment of two bar magnets are M 1 → and M 2 → . If angle between them is θ , then write the value of resultant magnetic moment.

Given, Magnetic moment of two bar magnet is M 1 a n d M 2 Angle between them is θ Therefore, Resultant magnetic moment= M 1 2 + M 2 2 + 2 M 1 M 2 C o s θ This is our required answer.

The magnetic moment of two bar magnets are M 1 → and M 2 → . If angle between them is θ , then write the value of resultant magnetic moment.

Given, Magnetic moment of two bar magnet is M 1 a n d M 2 Angle between them is θ Therefore, Resultant magnetic moment= M 1 2 + M 2 2 + 2 M 1 M 2 C o s θ This is our required answer.

The pole strength of poles of a bar magnet of effective length 0 . 1 m is 40 A - m . Calculate it's magnetic moment.

We know that, Pole strength is a quantity corresponding to the amount of magnetic flux emanating from a given magnetic pole and expressed in terms of the unit magnetic pole. and Magnetic moment is the property of a magnet that interacts with an applied field to give a mechanical moment. According to question Pole strength, m = 40 A m effective length, 2 l = 0 . 1 m Magnetic moment, M = m ( 2 l ) M = 40 × 0 . 1 M = 4 A m 2

Define Curie temperature.

Curie temperature is defined as the temperature at which certain materials lose their permanent magnetic properties, to be replaced by induced magnetism. The term Curie temperature is named after Pierre Curie who showed that magnetism was lost at critical temperature.

Define angle of dip. Write value of angle of dip at magnetic poles of earth.

(i) Angle of dip or magnetic inclination- The angle made by the earth’s total magnetic field with the horizontal direction in the magnetic meridian is called angle of dip δ at any place. (ii)At Magnetic poles, the value of this angle is 90 °

Obtain an expression for magnetic moment of an orbital electron.

Let us suppose, an electron revolving around a nucleus in an atom. As we know that, the electron is a negatively charged particle, so atom will act as a current carrying loop and the magnetic dipole moment of an electron is given by- M = I A Here, I is current and A is the area of the cross section. I = e t M = e t ( πr 2 ) where, I= current e=electron t=time ∵ t = 2 πr v Now, by putting the value of time t, we get, magnetic moment, M = e 2 πr × πr 2 v M = evr 2

Write definition of Curie temperature for ferromagnetic substances.

The temperature at which a ferromagnetic substance becomes para magnetic is called curie temperature of curie point T c Cause : when ferromagnetic sample heated, its magnetization decreases due to the increase in the administration of its domains. At high temperature, the domain structure disintegrates & the ferromagnetic substance becomes para magnetic