Asked by Annoyingmous

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=
Answered by drwls
Are the batteries and resistors in parallel or series?
It makes a difference.

There is no "circuit below"
Answered by Annoyingmous
i would like to post the photo of it but i have no clue how
Answered by BoobleGum
what find t?
it is correct: t = -ln(0.25)*RC ? and what shuld be R?
Answered by Annoyingmous
maybe R=Req? i'm not sure
Answered by trustee
t=-ln(0.25)*RC correct


what is answer for 1c,1d
Answered by BoobleGum
i1 = 0
i2 = i3 = U/(2*R)
U on Cap = (3/4)*(2U)

give pliz form on 1d
Answered by Yu
BoobleGum, what is the value for U please?
Answered by BoobleGum
I have both batteries on 5 volts, and voltage on the condenser of 7.5 volts
Answered by Tia
Sorry Booblegum, what is value U? I don't get it
Answered by FLu
Did somebody figure out problem after the first question please?

I don't seem to get it with above formula.
Answered by FLu
What value is U by the way?
Answered by Phy
Flu, U is the voltage of the battery
Answered by 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)
Answered by Phy
Are these the formulas for 2nd problem?
Answered by Phy
Yeah, only c) worked for me
Answered by FLu
Phy, yes second problem. Unfortunately, I could also not get it. Does someone know the right formula please?
Answered by Phy
Do you know 1st c) and d) ??
And 3rd problem??
Answered by Io
1st) c) 1.5*V
d) t=-ln(0.25)*2*R*C
Answered by Nur
Problem 2 please help with formula!
Answered by FLu
Thanks lo, can you help with Problem 2?
Answered by 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?
Answered by Sat
it does not work for me also
Answered by robbo
has anyone figured out 1d yet???/ PLEASE!? I really need it!
Answered by GR
1 d)
The correct Formula is
t=-ln(0.25)*R*C

Where R is the thevenin resistance in the capacitor
Where Rth = [R||R + R]
Answered by robbo
GR, the answer isn't coming with that formula!
Answered by TA
Robbo, can you post your values plz?
Answered by TA
hi GR, what is your values plz for Q1
Answered by 03
Second problem last formula please? I used T = 2*pi*sqr(C*L), but it gives wrong answer. T/ 4 as well.....
Answered by Hu
03 do you have second proble formula d) and e) please?
Answered by 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?
Answered by 03
d)L*I^2/2
e)Sqr(2*C*U)
Answered by TA
I got the answer, if you give the correct answer for 1c,1d. Thnx
Answered by 03
FLu what is c* capacitor ?!
Answered by Physics
GR my values for Ques1 d part are V=25 C=401 R=37
Answered by 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?
Answered by 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.
Answered by TA
I got the answer, if you give the correct answer for 1d. Thnx
Answered by P
Pls. tell any one ans I am working on 1d
Answered by TA
I got the answer, answer for FLU is WRONG
Answered by FLu
Can you give me the formula then TA please for d) and e) please?
Answered by TA
1D needs TH RESISTANCE . pLS EXPRESSION
for TH Rx for ths circuit. wrong answers given
Answered by FLu
TA I meant Problem 2 d) and e) not 1. Do you have them please?
Answered by Hy
Problem 2 d) and e) formula does not work please help!
Answered by Mart
Problem 2 d) and e) and f) please? Something dioes not work
Answered by Aristoitle
1.d .375 (R*C)

2.d 0
2.e 0.125
Answered by TA
You have to PAY Buddy, just like on Campus.
Answered by W
anyone get #6???
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