Asked by abdul rahman

A circuit consists of a self inductor of L=0.003 H in series with a resistor R1=5 Ohm. Parallel to these is a resistor R2=10 Ohm. A battery of V0=9 volt is driving the circuit.

Current has been running for 10 minutes.

(a) How much energy (in Joules) is now stored in the self-inductor.

(b) How much power (in Watt) is then generated by the battery into the circuit? (ignore internal resistance of the battery).

The connection to the battery is now broken (so that the battery is not connected to the circuit anymore).

(c) How long will it take (in seconds) for the current through R1 to be reduced by 50%?

(d) How long does it take (in seconds) till the energy stored in the self-inductor has been reduced by 50%?

(e) How long will it take (in seconds) for the current in R2 to be reduced by 50% (compared to the highest value right after the battery is disconnected)?
Answered by abdul rahman
plz help.....!
Answered by s
I can tell you a) & b)
a) Assuming after 10 min I=Imax then
I1=V/R1 and so the energy is 1/2*L*I1
b) I=V/Req (Req=(R1*R2)/(R1+R2)) So P=I*V
Answered by abdul rahman
Thnx :) a) n b) are correct ! plz some one for c), d) n e) parts ???
Answered by s
For c) & e):For broken connection of V then Req is R1+R2 so the equation is :
Imax/2=Imax*e^((-Req/L)*t) and Imax is the Imax from before the connection with the V was broken so Imax=V/R where R=(R1*R2)/(R1+R2)
Answered by s
I still can't get the solution for d if i manage to get it i'll post it
Answered by abdul rahman
can u plz tell the answers in numerals for time in parts c) n e). I am unable to solve it correctly !
Answered by s
0.0001386 both. Spent a little time and put the equation in Wolfram alpha it's online calculator and it's very helpfull in general
Answered by abdul rahman
thnx c n e are correct !
Answered by abdul rahman
plz lemme knw the b) part when u are able to figure out !
Answered by Anonymous
d)since you have find a) then first you should find what the current is for the half energy 0.00486/2=0.00243 so 0.00243=1/2*0.003*I^2 so I=1.27279.the max current in the self inductor was i=9/5=1.8A so the equation is 1.27279=1.8*e^(-(15/0.003)*t)(R=(5+10)Ù because now the connection with v is broken)so t=0.0000693135
Answered by FLu
Can somebody help with Problem: Displacement Current please?

I thought the formula is:
(1.25663706*10^-6*0.04*0.2*0.0705)/(2*pi*0.05^2)

However, I am not getting the correctr answer.
Answered by Anonymous
FLu the formoula is (ì0*I)/(2*pi*r) and ì0=4*pi*10^-7
Answered by FLu
Thanks Anonymous!

Do you have by any chance the answer for Problem:

Opening a Switch on an RL Circuit
b) and c)

I could figure out a)V_0/R_1
the other one seems more complicated.

Can you help please?
Answered by Anonymous
FLu b) is the equation
I0*e^((-(R1+R2)/L)*t) I had no luck with the others
Answered by FLu
Many thanks Anonymous!

I got d) 100

Opening Switch on an RL Circuit:
b) seems in a way easier as most of the letters are not accepted only R1, R2 and V0.

Did somebody managed it yet?
Answered by dd
a and d please
Answered by FLu
dd, I have provided a and b already just have a look above.

Anyone for c) please?
Answered by My
Did somebody found c) yet please!?
Answered by FLu
Sorry meant a and d. b) was provided by Anonymous.

If anybody knows c), thanks in advance!
Answered by Ur
Yes, please answer c) please!
Answered by Lora
c) please!
Answered by Gema
c) Anyone?
Answered by FLu
Anyone for c) guys please?
Answered by My
Was someone successful with c)?
Answered by Supraconductor
for C)... divide the b) by 2
Answered by Anony
PLEASE NUMERICAL ANSWERS FOR A) AND B)
Answered by FLu
Thanks Supraconductor.
I could not figure it out. Is it this:

V_0*e^(R_1+R_2)

Thanks in advance!
Answered by My
Having problems with c) is well, was somebody able to come up with the expression?
Answered by Haet
Expression for c) please?
Answered by Ula
I tried it out now with the hint of Supraconductor but could not figured out. Did somebody manage it please?
Answered by Terry
c) please anyone!
Answered by Ur
Please c)?
Answered by hmmmm
c)0.0001386
Answered by Ur
Thanks hmmmm, I meant Problem:
Opening a Switch on an RL Circuit
Do you have c)?
Answered by FLu
Anyone for Problem:

Opening a Switch on an RL Circuit: c)?

Thanks.
Answered by Anonymous
Finally c)(V_0*(R_1+R_2))/R_1
Answered by Anonymous
(Part c for RL circuit)
Answered by FLu
Great many thanks Anonymous!
Answered by P
Please tell RL Circuit I2 I3 for b and c
ASAP