Explain polarisation of polar molecule in uniform electric field.

Vedclass pdf generator app on play store
Vedclass iOS app on app store

The permanent dipole moment of polar molecules is zero because the different permanent dipoles are oriented randomly due to thermal agitation, so the total dipole moment is zero.

When an external field is applied the individual dipole moments tend to align with the field. When summed over all the molecules there is then a net dipole moment in the direction of the external field means the dielectric is polarized which is shown in above figure.

The extent of polarization depends on the relative strength of two mutually opposite factors. The dipole potential energy in the external field tending to align the dipoles with the field and thermal energy tending to disturb the alignment.

Generally, the alignment effect is more important for polar molecules.

898-s114

Similar Questions

How does the polarised dielectric modify the original external field inside it ?

In one design of capacitor thin sheets ot metal of area $80\  mm \times 80\  mm$ sandwich between them a piece of paper whose thickness is $40\ μm$. The relative permittivity of the paper is $4.0$ and its dielectric strength is $20\ MVm^{-1}$. Calculate the maximum charge that can be put on the capacitor

[permittivity of free space $ = 9 \times 10^{-12}\  Fm^{-1}$]

A parallel plate capacitor $\mathrm{C}$ with plates of unit area and separation $\mathrm{d}$ is filled with a liquid of dielectric constant $\mathrm{K}=2$. The level of liquid is $\frac{\mathrm{d}}{3}$ initially. Suppose the liquid level decreases at a constant speed $V,$ the time constant as a function of time $t$ is Figure: $Image$

  • [IIT 2008]

With the rise in temperature, the dielectric constant $K$ of a liquid

A parallel plate capacitor has plate of length $'l',$ width $'w'$ and separation of plates is $'d'.$ It is connected to a battery of emf $V$. A dielectric slab of the same thickness '$d$' and of dielectric constant $k =4$ is being inserted between the plates of the capacitor. At what length of the slab inside plates, will be energy stored in the capacitor be two times the initial energy stored$?$

  • [JEE MAIN 2020]