Physics 39 Capacitors (24 of 37) Find C for a Spherical Capacitor in 2 Spherical Dielectrics

In this video I will find the capacitance of a spherical capacitor inside 2 spherical dielectrics.

Next video can be seen at:

[RakeshKumar-ypht]

Gauss man did everything possible to relate flux, charged enclosed and electric field with each other. And this 10 minutes video did everything possible to put all those efforts in vain

[linlinlin]

OMG this is really helpful when I struggle with where to find the charge

[anonimasah]

where does the charge reside on the outer sphere? if you shine a UV lamp on the outer sphere will negative charge leave the outer sphere indicating that the charge resides on the outside?

[CHEESYhairyGASH]

When you calculate the second electric field for the outermost dielectric layer, you are basically taking a Gaussian surface and then acquiring an expression for the Electric field from there. However, you did not take into account the inner most dielectric's relative permittivity? Is this something we can do in general? Just ignore the inner dielectric when taking a Gaussian surface in an outer dielectric?

For example, if there were a third dielectric, would the Gaussian surface used to calculate the Electric field within that third dielectric would simple ignore the first and second layers of dielectric? i.e. k1 and k2 would not appear in this third layer's electric field expression?

In general when composing an expression for the electric field in dielectric layer "n", do we only consider k(n) and forget about k(n-1), k(n-2), k(n-3)... and so on?

[Abhinav_Agrawal]

how we got the electric field at 3R/2 can you please explain

[PApaSmurfCDMCMD]

shouldnt you take into account that each layer has a different charge, q1 and q2? I had a similar question but the radii were arbitrary, shouldnt C1 = Q1/V1 and C2 = Q2/V2, then solve for total capacitance of capacitors in series: 1/C = 1/C1 + 1/C2.

[deadawake]

Thanks a lot! Q: How did you calculte the electric field. if i assume the the inner sphere has Q ammount of charge, and as result the middle sphere has -Q and the outer has Q again.
if I'm using gaussian to determine the field between the middle and the outer so i get E2= 0 (because the total charge inside is 0) . I know I wrong somewhere but can't understand where...

[caseyli]

I understand that the electric field can be derived from Coloumb's law, but I was wondering why the same result does not occur when you use Gauss's law, which states that the closed line integral of E is equal to Qenclosed/epsilon? If you use Gauss's law, E = q/(2 pi r epsilon), assuming that the area is 2pi r is the area.

[clashingallthetime]

Is it necessary to integrate?
What about depending on our prior knowledge? (We have previously derived the equation of a spherical capacitor.)
Hence we can consider this multi-dielectric capacitor as two spherical capacitors connected on series.
Is it fine to do so??🤔

[Kreln]

*Imagine this...*
*1R and it's interior... A conductive solid/liquid sphere of ferromagnetic iron and nickle...*
*K1... An insulating silica mantle, (silica being the primary ingredient in common glass...)*
*2R... A saline ocean covered planitary crust...*
*K2... A lower atmosphere...*
*3R... An upper atmosphere...*
*Then consider the fact that as can be observed from the aurora at the North and South poles, there is evidence of enough current and voltage to allow the visible ionization of the atmosphere, as well as the fact that the Earth is on an eliptical orbit that periodically brings it closer to and then and further from the sun... Is it not entirely plausible that the Earth and other planetary bodies act as spherical capacitors with inductive cores that are able to charge and discharge both voltage and current, and thus electrical power? And couldn't this charging and discharging cycle possibly help to explain, when combined with the the movement of daily rotation and yearly orbit, the generation of our magnetic field and geothermal heat & Vulcanism?*

[johnnybatafljeska]

Why aren't we taking infinity as reference point for potential? from infinity -->3R 3R--->2R, 2R--->R, R---->0(last integral is zero) ..

[khushantrana]

Sir why we are taking limit from R to 2R? Not from 2R to R??