magnetism and matter

magnets

Force b/w two pole m1 and m2

k m1m2/ r²

k= u₀ /4n

paramagnetism is universal

true false

false

dimagnetism is universal and present everywhere

superconductor is a perfect diamagnet

true false

true

metal form at very low temp

u_r = 0   u=0    X= -1

this is called meissner effect

assertion- magnetic field lines are continuous and form closed loops

reason- magnetic monopoles do not exist

true and true reason

magnetic permeability and magnetic susceptibility is scalar or vector

scalar, scalar

magnetic susceptibility unit and dimension with formula

no unit and dimension

M= X H

magnetic permeability formula

B= uH

u= u₀ u_r

Magnetisation M scalar or vector

formula 

units and dimension

vector

M= magnetic moment/ volume

dimension by unit= Am^-1

Magnetic intensity Magnetic field strength H

scalar or vector

formula 

units and dimension

vector 

B= u₀ (H+M)

dimenion easily by unit= Am^-1

magnetic flux

scalar or vector

formula 

units and dimension

scalar

o= BA

unit= weber

dimension= M¹L²T^-2A^-1

magnetic moment M’

scalar or vector

formula 

units and dimension

vector

Magnetisation= M’/volume

unit= Am²

dimension= AL²

permanent magnets are

Substances, which at room temperature, retain their ferromagnetic property for a long period of time

relative magnetic permeability and mag susceptibility relation

u_r = 1+X

gauss law for magnetism states

magnetic flux through a closed surface is zero

B.dA= 0

if a bar magnet is kept in a uniform magnetic field then force is

zero

a bar magnet of magnetic moment m, at a distance r from its mid-point, where r >>l, the magnetic field B due to this bar is,

B =µ₀ m/ 2πr³ (along axis)

B = - µ₀ m/ 4πr³ (along equator)

diamagnetic ferroemgnetic and paramagnetic difference table

answer of 1

answer of 2

answer of 3

answer of 4

1) q1 and q2 not on magnetic field so not in equilibrium

2) stable when line perpendicular is anti parallel and axial line is parallel

unstable when equitorial line is parallel and axial line is anti parallel

3) lowest potential energy is for axial line because of negative sign and stable in axial line is q6

which of the lines are right and why wrong

1. magnetic lines closed loop bnati hai straight nahi

2. magnetic lines cross nhi hoti

3. correct hai closed loop hai

4. the lines at end should meet

5. correct

6. wrong because arrow ki direction ek plate se nikalke doosre me jarhi hai elec field ki trah

7. north se south field jarhi hai pr pura straight line nhi curve hona chahiye

geometric strength is less than measured length

false

magnetic moment formula

M =ml

m= pole strength

Magnetic moment depends on

volume

pole strength~ area

M= ml= area x length= volume