Posted by Annoyingmous on .
The circuit below consists of three identical resistors each with resistance R=7 Ohm, two identical batteries with emfs E=9 V, and a capacitor with capacitance C=651 μF. The capacitor is initially uncharged at t = 0.
(a) After a very very long time, t≫RC, what is the current i1 (in A)?
i1=
(b) After a very very long time, t≫RC, what are the currents i2 and i3 (in A)?
i2=
i3=
(c) After a very very long time, t≫RC, what is the magnitude of the voltage (in V ) across the capacitor ?
VC=
(d) Assuming that the capacitor starts uncharged, how long will it take (in seconds) for the voltage across the capacitor to reach 3/4 of its maximum value?
t=

Physics 
drwls,
Are the batteries and resistors in parallel or series?
It makes a difference.
There is no "circuit below" 
Physics 
Annoyingmous,
i would like to post the photo of it but i have no clue how

Physics 
BoobleGum,
what find t?
it is correct: t = ln(0.25)*RC ? and what shuld be R? 
Physics 
Annoyingmous,
maybe R=Req? i'm not sure

Physics 
trustee,
t=ln(0.25)*RC correct
what is answer for 1c,1d 
Physics 
BoobleGum,
i1 = 0
i2 = i3 = U/(2*R)
U on Cap = (3/4)*(2U)
give pliz form on 1d 
Physics 
Yu,
BoobleGum, what is the value for U please?

Physics 
BoobleGum,
I have both batteries on 5 volts, and voltage on the condenser of 7.5 volts

Physics 
Tia,
Sorry Booblegum, what is value U? I don't get it

Physics 
FLu,
Did somebody figure out problem after the first question please?
I don't seem to get it with above formula. 
Physics 
FLu,
What value is U by the way?

Physics 
Phy,
Flu, U is the voltage of the battery

Physics 
FLu,
Many thanks Phy!
Could you help with this please. This was provide by hmmmm and anonymous but only c) works for me.
Did you get this:
formula for question 2
a)B=meu_0*N*I/l
b)L=meu_0*N^2*A//l
c)I=V/R
d)U=1/2(LI^2) 
Physics 
Phy,
Are these the formulas for 2nd problem?

Physics 
Phy,
Yeah, only c) worked for me

Physics 
FLu,
Phy, yes second problem. Unfortunately, I could also not get it. Does someone know the right formula please?

Physics 
Phy,
Do you know 1st c) and d) ??
And 3rd problem?? 
Physics 
Io,
1st) c) 1.5*V
d) t=ln(0.25)*2*R*C 
Physics 
Nur,
Problem 2 please help with formula!

Physics 
FLu,
Thanks lo, can you help with Problem 2?

Physics 
BoobleGum,
Io,
The formula Q1 d)t=ln(0.25)*2*R*C doesn't work for me, you can check it, there can be there a mistake is? 
Physics 
Sat,
it does not work for me also

Physics 
robbo,
has anyone figured out 1d yet???/ PLEASE!? I really need it!

Physics 
GR,
1 d)
The correct Formula is
t=ln(0.25)*R*C
Where R is the thevenin resistance in the capacitor
Where Rth = [RR + R] 
Physics 
robbo,
GR, the answer isn't coming with that formula!

Physics 
TA,
Robbo, can you post your values plz?

Physics 
TA,
hi GR, what is your values plz for Q1

Physics 
03,
Second problem last formula please? I used T = 2*pi*sqr(C*L), but it gives wrong answer. T/ 4 as well.....

Physics 
Hu,
03 do you have second proble formula d) and e) please?

Physics 
FLu,
03 this was mentioned by Slylar in another thread but did not work for me for f) problem 2:
And for 2f is sqrt(2c*capacitor)*pi/2
do you have formula for problem 2) d) and e) please? 
Physics 
03,
d)L*I^2/2
e)Sqr(2*C*U) 
Physics 
TA,
I got the answer, if you give the correct answer for 1c,1d. Thnx

Physics 
03,
FLu what is c* capacitor ?!

Physics 
Physics,
GR my values for Ques1 d part are V=25 C=401 R=37

Physics 
FLu,
Sorry 03, I think Sylar meant the answer from c) and the capacitor value.
I copy the message below:
Ah, ok. For d)You have the inductance for answer 2b. And the time for 2c.
So. The answer will be
2b*2c^2/2.
And for 2f is sqrt(2c*capacitor)*pi/2
can you tell me the value for I and L please in d) and also what is value U in e) please 03? 
Physics 
Physics,
TA please give ans or formula for any ques tion you have got. 1c is 1.5*V V is volatage of the battery.

Physics 
TA,
I got the answer, if you give the correct answer for 1d. Thnx

Physics 
P,
Pls. tell any one ans I am working on 1d

Physics 
TA,
I got the answer, answer for FLU is WRONG

Physics 
FLu,
Can you give me the formula then TA please for d) and e) please?

Physics 
TA,
1D needs TH RESISTANCE . pLS EXPRESSION
for TH Rx for ths circuit. wrong answers given 
Physics 
FLu,
TA I meant Problem 2 d) and e) not 1. Do you have them please?

Physics 
Hy,
Problem 2 d) and e) formula does not work please help!

Physics 
Mart,
Problem 2 d) and e) and f) please? Something dioes not work

Physics 
Aristoitle,
1.d .375 (R*C)
2.d 0
2.e 0.125 
Physics 
TA,
You have to PAY Buddy, just like on Campus.

Physics 
W,
anyone get #6???