I posted this in the advanced section, but glancing over the problems there I realized this probably belongs here.[/B]
Hello everyone. I hope this is the right category. I am in desperate need of help. I have no High School Education. But a few weeks ago I participated in an entrance exam for a university (very well known for physics actually) in my country of residence.
Long story short, I passed all exams (11) except 2 math exams, did best in physics but am 0.1 short of passing overall.
Physics were two exams (oral and written). In the oral one the examiner made up problems on the fly. I solved them well and quick. But she made up this exact problem Starting at 33:33 Minutes that Mr. Walter Lewin uses.
is his way wrong?
I am very comfortable with circuits but I did Walter Lewins courses after my first completion of Giancolis Book and then Ohanian.
I found his way to be much faster.
The Examiner asked me for I 1 (Current through the left loop) and R3 said all other things (I 2, R1, R2, I3) are known.
I told them (a physics teacher and a professor of chemistry were my examiners) that usually one would solve this by using Kirchhoffs loop rule.
But I know a faster way from youtube. The Examiner asked me to go ahead then and use my way.
But while writing my equations (same as Lewin in the Video) she kept saying I was wrong as I1 and I2 don't go through R3.
While I was actually just one step (a total of 3 away from solving).
I got a B.
Though I was sure I wasn't wrong as I practiced the death out of this.
I went back that evening and luckily found a problem in Giancolis Book that is basically the same.
I worked this out and several others easily with the equations I had used at the exams.
I showed the professor and he agreed that my way gives the correct solution every time. But insisted it just gives the right answers but is still wrong. So they would end up only bumping me to an A if it would help me pass the overall exam.
I found out that they made a mistake during this too.
When I tried to reason that just three steps and two equations is faster.
I noticed the Professor realize a mistake they made, though he didn't admit it. He thought I 1 was directly solvable in one equation with Kirchhoffs rules. As the problem they had in mind was with R3 given. Luckily on the paper she wrote down R 3 and I 1 aren't given.
Which I think swayed him to give me the A.
Anyhow they didn't even give me the A, so I have a meeting tomorrow. A+ would push to 0.03 under Pass which qualifies as review (which could get me in).
I thought it's not wrong as the Potential Difference is the Integral of E x d. And the closed loop Integral or an Integral from A to A would always be zero. (Which is something I mentioned at our meeting).
And I3 is just the difference of I2 and I1.
But I'm not a hundred percent sure. Is his way actually scientifically wrong?
I am sooo sorry to burden you. I am 30 years old. I am trying to fulfill my dream here. I have another shot but financially it's a burden to wait another year. ( I saved a few years and quit my job to study for this exam and be able to attend Uni)
If it isn't wrong. HOW DO I politely but very indisputably convey this tomorrow?
I am eternally grateful to you.