LC circuit, space between dielectric plates

AI Thread Summary
The discussion revolves around calculating the separation between capacitor plates filled with a dielectric, given the maximum electric field and dielectric constant. The relevant equation for capacitance is provided, but the user struggles with multiple unknowns in the problem. They initially attempt to use the electric field equation to find surface charge density but feel stuck. A suggestion to calculate the maximum potential difference between the plates helps them progress, ultimately allowing them to determine both the separation and the area of the plates. The exchange highlights the importance of understanding relationships between electric field, potential difference, and plate separation in capacitor physics.
skate_nerd
Messages
174
Reaction score
0

Homework Statement



If the max E-field in the capacitor is E=1.2(103) N/C and the space between the plates is filled with a dielectric of constant 100,000, what is the separation between the plates?

Homework Equations



I know C=kεoA/d where k is the dielectric constant, A is the area of one of the plates, and d is the separation.

The Attempt at a Solution



So this problem came with multiple parts. Initially we are given the capacitor has capacitance 30μF, the inductor has inductance 0.7H, and the total energy is 44μJ. Its a simple closed loop with no battery. Parts a-e i found that the time for the energy to reach the inductor is 7.2ms, the charge on one side of the capacitor at t=0 is 51.4μC, the current at 7.2ms is 11.2mA, the inductor has length 4cm, radius 2.8cm, and 3010 turns, and the B-field in the inductor is 1.06mT.

The question I'm asking about is part f...the next part g asks for the area of one of the plates.
I just simply don't see how there is enough information to deduce either the space between the plates or the area of one. The equation above shows that that means there is two unknowns.
Seeing as we are given the E-field strength, I thought we could maybe use

E=σ/kεo,

I solve for σ, and plugged in everything else, and the value I got out for σ was 1.06. The same value I got for the B-field strength...I'm just not really sure where to go with any of this, been stuck for a while.
 
Physics news on Phys.org
Can you find the maximum potential difference Vmax between the plates of the capacitor? If so, then you can find the distance d between the plates using a relationship among Vmax, Emax, and d.
 
Ahhhh thank you. I wasn't aware there was a way a could find the potential difference in the plates. Now I found the separation, and in turn the area. I appreciate the help!
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'Collision of a bullet on a rod-string system: query'
In this question, I have a question. I am NOT trying to solve it, but it is just a conceptual question. Consider the point on the rod, which connects the string and the rod. My question: just before and after the collision, is ANGULAR momentum CONSERVED about this point? Lets call the point which connects the string and rod as P. Why am I asking this? : it is clear from the scenario that the point of concern, which connects the string and the rod, moves in a circular path due to the string...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top