magnetism

Question 1

magnetic length

Answer 1

dist btw 2 poles of magnet

-slightly less than geographical length

Question 2

magnetic length/geographical length

Answer 2

0.84

Question 3

magnetic dipole

Answer 3

2 equal and opp seperated by a very small distance

m=qm x 2l

Question 4

si unit of magnetic dipole

Answer 4

Am^2

J/T

Question 5

properties of magnetic field lines

Answer 5

• N to S pole
• do not intersect if they do 2 directions
• contract in length and expand side wise-explains attraction and repulsion
• start and end in magnet normally

Question 6

how bar magnet is equivalent to solenoid?

Answer 6

-solenoid suspended freely faces north and south direction
-2 solenoids feel attraction or repulsion - makes solenoid act as N or S pole
-lines of forces are similar
-both
B = mo/4(pi) 2m/r^3
axial

Question 7

B axial

Answer 7

mo/4pi 2m/r^3

Question 8

B equitorial

Answer 8

mo/4pi m/r^3

Question 9

magnetising field

Answer 9

exist in vaccum and induce magnet

Question 10

magnetic induction B

Answer 10

no. of magnetic field lines passing through per unit area normally

Question 11

units of magnetic induction

Answer 11

Tesla
webber/m^2
N/Am
J/Am^2

Question 12

Magnetising field intensity H

Answer 12

no of ampere turns flowing round the unit length of solenoid recquired to produce the given magnetising field

H=nI

Question 13

units of magnetising field intensity

Answer 13

A/m
N/m^2T^1
J/mWb

Question 14

intensity of magnetisation M

Answer 14

M = m/v

Question 15

Magnetic permiabilty

Answer 15

mu= B/H

UNIT:Tm/A

Question 16

susceptibility

Answer 16

M/H

no units

Question 17

relation btw permeability and susceptibility

Answer 17

B=mu(H+M)

permeability =1+susceptibility

Question 18

current loop as a magnetic dipole

Answer 18

B= mu I a^2 / 2r^3

B= mu 2IA/ 4(pi) r^3

Question 19

consequence of gauss’s law

Answer 19

• no source or sinks of magnetic field in a closed surface
• magnetic poles always exist unlike
• magnetic lines of forces: input=output