capacitors + fluids
very small doubt.
case 1: lower plate has -sigma charge density
case 2: lower plates has +sigma charge density
will liquid rise in both the cases ??
i believe liq will rise only in case 2 since electric field will be directed upwards. if i am correct what exactly will happen in case 1 ??
40 Replies
@Gyro Gearloose
Note for OP
+solved @user1 @user2... to close the thread when your doubt is solved. Mention the users who helped you solve the doubt. This will be added to their stats.case 2 will be something like this. a particle just on top of liq will experience net force sigma/epsilon in upwards dirn ?
Why wouldn't case 1 also result in rise
field would be downwards
basically every charge opposite of it
Net force would be zero
Liquid ek height tk rise krega or fur equilibrium condition ban jayega Electric force mg de balance ho jayega
Dono case me rise krega ig kyuki induced charge density to hamesha opposite hi hogi
electric force kitna aaega
i am getting sigma/epsilon which is def wrong
ig ill get my ans to this when i get correct electric force
Wait a min
Net electric field will be sigma/E-Sigma induced/2E
E is epsilon
why
kaise
Induced electric field dielectric ka hota hai na
Sigma induced /2E
Sigma/E capacitor ka
+sigma (ind) and -sigma(ind) ka force cancel nahi ho jayega
kyu cancle ho jayega
Wait letme share a picture
we are finding force on red dot right?
Yes
red dot pe ek positive test charge assume kare toh +sigma(ind) will push it and -sigma(ind) will pull it
both magnitude = sigma(ind) /2epsilon
Ek point samjh kar mat mano force ham pure liquid par nikalege na jo Pura volume occupy krega us pure liquid me also capacitor ka bhi bhi to electric force rhega to ek net upward field rhega
Is net upward force ko ham gravitational force se balance karege
Ek positive charge hi kyu Maan Rahe hain
We are talking about induced charges rn
In case 2 we can assume +ve cause of charge distribution in that manner (rn talking inly about in which case liq rises)
should i resolve forces about com of the mass above the plate
Yes assume the height to be h and com at h/2
red is force due to induced charges and blue is due to given charges , not equal in magnitude
sigma/E - sigma(ind)/E
And then
this is wrong
atleast acc to what real potato said
if i get net electric field i can just equate forces
Tumne poora q bheja hai na
Not sure
haan han
check for yourself phy galaxy ka hai
illustration 2.51
Ima try now
Jo topmost point hai liquid ka us point par field + sigma - sigma and niche wale surface par jo induced charge density aai hai uske karan hai
Islie net electric field aisa ayega
I know this is a bit confusing but yeah aisa hi hoga
wapis topmost point pe field kyu nikalne lage , mg toh com se lagega na T-T
so liq ke andar h/2 heigt pe field nikalni chahiye
Ha lekin fir wo complicate ho jayega
Us point par fir induced electric field likhna pdegi
lhs mei A nhi aayega mb
fir topmost point pe electric field nikal ke kya karoge
I did smthn like this
Total mass likh sakte hai na ham fluid ka multiply by g= gravitational force
whi toh fluid ka mg toh com se lagega na
Lhs A nhi aayega mb
Is mine crct
I dont know abt centre of mass thing like fluid par jaha bhi gravitational force lagate hai waha kabhi com ka concept nhi lagaya
baat toh sahi h
bernoulli's me bhi ham 'h' lete the tho
Got some solution ??
help 🙏
+solved @Real potato
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