# Electromagnetism

I am having trouble in certain questions which involve the concept of earthing and potential among plates ! can you plz help by suggesting any methods about that? and 2nd ques, when we overflow a bottle we see the surface is not plane but curved ! what is the radius of that curve ? 3rd one there is a frustum of cone (which is formed by cutting half of a cone ) and one charge $q$ is placed at the peak of original cone what is their force of interaction? I got $\theta \frac { \sigma q\quad ln(2) }{ 2\pi { \E }_{ 0 } }$ where $\theta$ is the half angle and $\sigma$ is the charge density on the frustum. Am I right?

Note by A Former Brilliant Member
4 years, 5 months ago

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What is the last one? Dimensions of the frustum?

- 4 years, 4 months ago

l/2 sl'nt height , R r'dius 'nd sigm' is ch'rge density of the frustum .

- 4 years, 4 months ago

got nything yet ? @Kishore S Shenoy

- 4 years, 4 months ago

What is $\ell$?

- 4 years, 4 months ago

it is just to s'y its v'lue is not going to 'ffect 'nswer 'nd it w's not even given in the question our interest lies only in the f'ct th't the cone is cut ex'ctly in h'lf

- 4 years, 4 months ago

Ohh, half. But still, I am getting in terms of $r_1$ and $r_2$

- 4 years, 4 months ago

m'y be you c'n you the h'lf 'ngle give in the question

- 4 years, 4 months ago

you were s'ying something bro @Kishore S Shenoy

- 4 years, 4 months ago

First one, can you show me the question

Second one, check this out

Third one, I am lazy enough to even try!

- 4 years, 4 months ago

no problem , you 'tle'st replied i'm h'ppy 'bout th't :)

- 4 years, 4 months ago

'nd th'nks for the second one :) it worked i 'm going to post 'n origin'l problem on it :)

- 4 years, 4 months ago

nobody helping me ? @Mark Hennings

- 4 years, 4 months ago

also help bro @Prakhar Bindal

- 4 years, 5 months ago

plz help sir @Mark Hennings @Josh Silverman

- 4 years, 5 months ago