Professor Lewin, I just solved this problem using nodal analysis as opposed mesh analysis. One obtains the same result by either method. In this case the mesh method, i.e. Kirchhoff's Loop Rule, appears to be the simpler as it requires solution of only two equations; whereas, the node method, Kirchhoff's Current Rule, requires solution of three equations, fortunately the three equations to be solved are trivial as the branch currents are known. Vb - Va = - 13 volts. (I took node b as the reference node; i.e. ground.) PS When solving Loop Rule equations I prefer to assume "downhill" is positive. Downhill positive is consistent with the passive sign convention and there are fewer minus signs to keep track of; the passive sign convention is that the voltage across an element is positive if and only if current enters its positive terminal.
current can only flow in a closed loop. some charge may flow for only a milli sec to make the electric potential in the wire everywhere the same *but that will be the end.*
Excuse me Sir.. if we solve this circuit by taking internal meshes.. then we got E1 as 8V . Kindly reply me that how can we solve this circuit with taking internal meshes
this video was made in 1997. If you have questions (only 1 at a time) refer to how many minutes into the video. Explore first whether you can find the answer on google.
Vb - Va = 18 - 5 = 13 Volts...because from b to a the electro motive force changes polarity from minus to plus and the voltage in the resistors in series is negative because the direction from b to a is changing polarity from positive to negative...I hope you understood it.
Taught me everything in 6 minutes compared to my prof who couldn’t explain it in 50 minutes . Thank you so much
thanks for the help! very clearly explained
You're welcome!
He makes the concept so easy
U deserve millions of views sir!!!
Ok but how to find volt potential ?
nice video, very helpful
Great and simple technique's sir to explain . our faculty does not know this much either too
Professor Lewin,
I just solved this problem using nodal analysis as opposed mesh analysis. One obtains the same result by either method. In this case the mesh method, i.e. Kirchhoff's Loop Rule, appears to be the simpler as it requires solution of only two equations; whereas, the node method, Kirchhoff's Current Rule, requires solution of three equations, fortunately the three equations to be solved are trivial as the branch currents are known. Vb - Va = - 13 volts. (I took node b as the reference node; i.e. ground.)
PS When solving Loop Rule equations I prefer to assume "downhill" is positive. Downhill positive is consistent with the passive sign convention and there are fewer minus signs to keep track of; the passive sign convention is that the voltage across an element is positive if and only if current enters its positive terminal.
Sir, If positive terminal of one battery is connected to negative terminal of another battery why does not current flow in the wire ?
current can only flow in a closed loop. some charge may flow for only a milli sec to make the electric potential in the wire everywhere the same *but that will be the end.*
I see that this semester on Physics 2 is providing me a very effective accumulation of informations.
👍 this is same ques asked in my mock test
Excuse me Sir.. if we solve this circuit by taking internal meshes.. then we got E1 as 8V . Kindly reply me that how can we solve this circuit with taking internal meshes
E1 as 8V
*E and V have different dimensions, thus this is wrong.*
Lectures by Walter Lewin. They will make you ♥ Physics.
Thanks sir for instant reply ♥
Do we lose the second 1 million joules to the internal resistor during the discharge?
question unclear
I’m
Sorry sir I commented this on the wrong video. My apologies.
thanks a lot
Watching ur video for the first time.. U sound like the famous #PatrickBetDavid
Hello sir. I've watched this vedio just now and it's about 4 years after it was uploaded. So can I ask questions on this topic ?
this video was made in 1997. If you have questions (only 1 at a time) refer to how many minutes into the video. Explore first whether you can find the answer on google.
Thank you so much Sir.
sir why the current,I is not included in your calculations?
watch the video again - it's 100% correct
PLZ MAKE A VIDEO SIR ON HOW TO SOLVE VERY COMPLEX "3D" CIRCUITS . HUGE FAN FROM INDIA : )
Sir , how can we send you our problems related to this topic?
right here
drive.google.com/file/d/1SYh8zL5q09HnmqhLYvGqGNkl5GRKSP6S/view?usp=drivesdk ---- sir, could you solve this ?
I do not solve problems for viewers. I teach Physics. Watch my lectures!
Oh ok!
@@lecturesbywalterlewin.they9259 cool prof
very nice
Vb - Va = - 13 Volt
How
Vb - Va = 18 - 5 = 13 Volts...because from b to a the electro motive force changes polarity from minus to plus and the voltage in the resistors in series is negative because the direction from b to a is changing polarity from positive to negative...I hope you understood it.