ELECTRIC POLARIZATION OF DIELECTRIC

ELECTRIC POLARIZATION OF DIELECTRIC:-

Under the action of an external applied electric field each dipole of dielectric readjust its position in such a way that its positive pole appears close to negative charged plate and negative pole appears closer to
positively charged plate such phenomenon is called electric polarization.
Electric polarization of dielectric increases the capacitance. Reason is given below:

REASON:-

The molecules of the dielectric material are readily polarised by the electric field between the capacitor plates. Polarised molecules have a distorted charge distribution that gives opposite 'ends' of the molecules an opposite charge .. these charge distributions are aligned by the capacitor field and create their own induced electric field.
This induced field is opposite in direction to the original field. As a consequence the net field strength between the plates is reduced as a result V also decrease by the relation (V=ED) hence the capacitance has been increased by the relation (C = Q/V)

CAPACITORS & CAPACITANCE OF PARALLEL PLATE CAPACITOR

CAPACITOR:-

               Capacitor is a charge storing device which consists of two parallel metal plates of same nature, surface area, magnitude of charge on each plate and surface charge density separated by small distance as
shown in fig
Magnitude of charge(Q) stored on each plate is directly proportional to potential difference(V) applied by the battery ie

DETERMINATION OF CHARGE ON ELECTRON BY MILLIKAN'S OIL DROP EXPERIMENT

DETERMINATION OF CHARGE ON ELECTRON BY MILLIKAN'S OIL DROP EXPERIMENT:-

C= Vacuumed Chamber     

W₁ & W₂= Two glass windows

P₁ & P₂=Two parallel metallic plates

H= Hole in upper plate

d= Separation between the plates

D= Oil drop

M= Magnified view of oil drop

x= Distance between oil drop with respect to lower plate

L= Convex lens

S= Source of light

A= Atomizer

V= Potential difference between the plates

ELECTRON VOLT

ELECTRON VOLT:-

 V_A=Potential of plate A                                                  

V_B=Potential of plate B

U_A=Potential Energy of plate A

U_B=Potential Energy of plate A

∆V=Potential Difference between the plates=      V_B-V_A

∆U=Electric Potential Energy difference of plates=U_B-U_A

ELECTRIC POTENTIAL AT A POINT DUE TO POINT CHARGE

ELECTRIC POTENTIAL AT A POINT DUE TO POINT CHARGE:-

We can derive this potential at point due to point charge by two methods one is by using gausses law and other is by general methods

By using gausses law

consider a charge. In order to calculate electric flux by gausses law we have to draw 

a Gaussian surface consider a spherical Gaussian surface as shown in fig. Charge is enclosed in it.

ELECTRIC FIELD AS POTENTIAL GRADIENT

ELECTRIC FIELD AS POTENTIAL GRADIENT:-

V_A=Potential of plate A                                                    

V_B=Potential of plate B

U_A=Potential Energy of plate A

U_B=Potential Energy of plate A

∆V=Potential Difference between the plates=      V_B-V_A

∆U=Electric Potential Energy difference of plates=U_B-U_A

ELECTRIC POTENTIAL DIFFERENCE (V) & ELECTRIC POTENTIAL ENERGY (U)

ELECTRIC POTENTIAL (V) & ELECTRIC POTENTIAL ENERGY(U):-

V_A=Potential of plate A

V_B=Potential of plate B

U_A=Potential Energy of plate A

U_B=Potential Energy of plate A

∆V=Potential Difference between the plates=      V_B-V_A

∆U=Electric Potential Energy difference of plates=U_B-U_A