Class 12 Complete physics part 1+2 Handwritten notes

ZAKI SAUDAGAR
Part-2


Physics
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CBSE CLASS 12 | CBSE 2023-24

Zaki Saudagar Physics

, Electromagnetic Waves

Introduction : -




Faraday law states that a changing in with time produces anE and Maxwell's proof
·




that
changing in with time will produce B. It means that change in either field a

(E / 5) with time produces the other fields .




·
After this discovery ,
Maxwell predicted that variation of & vectors perpendicular to
each other leads to disturbances in space , disturbances travels through
Electromagnetic
the space in form of waves , & these waves are called Electromagnetic waves
.



Maxwell'sExperiment : -




Consider capacitor is connected with battery
E
·
a




..
J
.
in the circuit
·
As maxwell's ,
observed that current flown
in the -> Conduction Current (Ic)
circuit
·
Similarly ,
current drawn area bet"the plates
->
Displacement current (In) a
I
behavior is same of
·
Physical Ic & ID .




·
He found that results were not consistent with the



Hi
Ampere's circuital Law
. This led to discovery of
I
Displacement current.
⑬ E ⑮ is
E

I
·
=
t
-




·
* -

E
E


t -
&
E

+ + -

- E



I
>




t - E
E E




fig : changing in Electric field.

Displacement Current : -




It is that current which
appears in the region in which the Electric field (or Electric flux) is
with time .
changing
-> In order to make Amperes circuital law logically consistent , this current was introduced .




Current :
Displacement
ID=dod
i. e
-

.




Then , Maxwell correct Ampere's circuital law : -




ou =
Moz foBdl=Mo(ts+I)
or


gB d1 (Ic +
Mo
3d
. =

,
,