Polarisation Of Dielectrics MCQ Level - 2 - Physics MCQ

When the dielectric is placed in an electric field, like between the parallel plates of a capacitor, the dipoles are created and they tend to align themselves parallel to the direction of the field.

Let ρ is the surface density of bound charge. Since, there is no free charge at interface.


Where  is the field produced by bound charges near the dielectric vaccum interface.

The correct answer is: 

Given system is a spherical capacitor. So, capacitance of system.

Now, potential of inner sphere will be equal to potential difference of the capacitor

The correct answer is: 30 V

Capacitance of a parallel plate capacitance with air is 

Capacitance of a same parallel plate capacitor with the introduction of a dielectric medium
,  where k is the dielectric constant of the medium. Dielectric constant is given as :

⇒ 

The capacity in air 
The capacity when dielectric slab of dielectric constant 5 is introduced between the plates

Capacity is increased by 66%
So, new capacity :

From (i) and (ii)

Now, volume charge density of bound charge,

Volume charge density at  
Since, the sphere is statically polarized.

If ρ is the surface density of free charges at the conductor dielectric interface.
Applying boundary condition of D vector.

Applying boundary condition of polarization


So, surface density of the bound charge at the conductor dielectric interface

The correct answer is: 

Capacity of a condenser is given as

The four plates are alternately connected. They form three capacitors in parallel.

The capacity of each capacitor is 

So, net capacity is 

The correct answer is:  

The free charge located at the centre of sphere will produce an electric field which will polarize the dielectric sphere.
Polarization of dielectric will produce bound charges.
Using Gauss’s law. 

Amount of bound charge enclosed by Gaussian surfaces