Energy in the inductor is

2 2 2

1 2 sin

2 2

UL Li Lqo t

Total energy

2

.

2

o

C L

T E U U q

C

  

Here^1

LC

 

Electromagnetic waves

16. Electric Flux

 E E.ds

Units N - m^2 /Coulomb or Volt meter.

17. Displacement Current
    The rate of change of electrical flux produces a
    current called displacement current “ i d”.
     Unlike conduction current displacement current
    exists when there is rate of change of electrical
    flux.
    The displacement current is found between the
    plates of a condenser during its charging or
    discharging.


18. Ampere -Maxwell’s Law

 B dl.    0 i ic d

 

. 0 c 0 E
B dl i d
dt

      

  

 

ic= The conduction current found in a conductor

carrying current.

id= Displacement current which is found between

the plates of a condenser which is discontinuous.

Displacement Current : d 0 E
i d
dt

  

19. Measurement of magnetic field
    A variable current is applied to a parallel plate
    capacitor.

(I) At point Q

B.dl  0 ci id

 

As id (^0)  (^) B.dl 0 ci
 
(II) At point P:

B.dl  0 ci id

 

But ic= 0 B.dl 0 di

 

20. Magnetic field between the plates
     The figure shows the cross-section of Electrical
    field between the plates of a condenser having
    the plates of radius R.
     The electric field is acting into the paper.

 The magnetic field at a distance “ r ” from the

axis is

B d. l ^0 i

  2

2 0 d 2.

i

B r r

R

    



0

2 d^2

B i r

R



 



21. Maxwell’s Equations
    (1) Gauss law for electricity

E d A q.  net/^0

 

(2) Gauss law for magnetism

B d A. ^0

 

(3) Faraday’s law

Electromagnetic waves

16. Electric Flux



17. Displacement Current
    


18. Ampere -Maxwell’s Law





19. Measurement of magnetic field
    20. Magnetic field between the plates
    





21. Maxwell’s Equations


22. Nature of electromagnetic waves
    . B

d

E dl

dt

  

  

(4) Lorentz Force

F q E v B   

  

22. Nature of electromagnetic waves
    Electric and magnetic fields oscillate sinusoidally
    in space and time in an electromagnetic wave,