magnetism

Question 1

direction of field outside bar magnet

Answer 1

N to S

Question 2

Causes of magnetism

Answer 2

1. orbital motion of e makes current loop act like magn dipole
2. mag moment of atom is due to orbital motion of e and spin etc
3. net mag moment is due to mag mom of all e

Question 3

I formula vector

Answer 3

Mnet vector/V

Question 4

net B inside is due to two factors. what are they?

Answer 4

1. internal factor (I)= due to alignment of dipole some magnetisation occurs
2. external factor (H() like current coil or ext field

Question 5

B net

Answer 5

Uo(H+I)

Question 6

I=

Answer 6

XH

Question 7

X and Ur for diamagnetic

Answer 7

-ve, small

Question 8

X and Ur for para

Answer 8

small +ve, slightly more than 1

Question 9

X and Ur for ferromagnetic

Answer 9

> > 1,&raquo_space;1

Question 10

exception for X (diamagnetic subs)

Answer 10

super conductor (X= -1)

Question 11

at what point does curies law become invalid

Answer 11

while lowering T, a stage comes where 100% at. dipoles are aligned perfectly with B ext. This is called saturation.

Question 12

example of temp magnet

Answer 12

soft iron

Question 13

explain phase transition

Answer 13

on increasing temp, ferromagnetic property decreases, and at some point, ferromagnetic material starts behaving like paramagnetic material

Question 14

phase transition occurs at which temp

Answer 14

curies temp (Tc)

Question 15

Gauss law of magnetism

Answer 15

mag flux through any closed surface is zero