My Computing - 6

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So I decided to approach Prof KV (EE) with my problem of translating my high-level language which our IBM 1620 couldn't read into the famous Fortran II.

KV was about five years senior to me and was living in a posh Guest House then. I walked in one night after dinner and shyly tapped on his door. When I explained to him the purpose of my visit, he welcomed me in and offered a plush sofa that I was not used to.

After my narration, he took a pen and paper and started with DIM 100 or maybe 200, and he involuntarily started explaining what that DIM was all about, looking at me benignly. And as he proceeded to write talking about all those DO loops and subroutines and fixed points and floating points and overflows and how the arctan is double-valued and how to fix it and every single detail, I could see he was enjoying.

Much later I happened to watch a TV program in which Bismillah Khan was at his best. And I noticed that while he was negotiating a tricky passage, his eyes were smiling since his lips were busy. I then recalled KV's eyes on that night two decades ago. KV was not just another great teacher...he was a Born Teacher. Born Teachers enjoy teaching irrespective of their audience reaction; and by and large their audience, whether they follow him or not, enjoy the sight. I read somewhere that Feynman used to enter his Jumbo Class Room a few minutes before his students did and when they entered, they found him smiling and drumming on the table before him...in anticipation of sheer pleasure.

After about an hour I thanked him and quit his room confident that Fortran II was just another evil spirit that has been exorcised once for all, and that I could write any other program if I sit down to it. That is another acid test of a Born Teacher...his students will no longer be afraid of the subject taught by him.

I then decided I owe a debt of gratitude to KV and would be happy if I get a chance to redeem it. As it turned out, I found him knocking on my door one Sunday morning two decades later with the request if I could coach his eldest daughter in Physics for some entrance exams...she had just passed her B Sc (Physics) from BHU. I welcomed the opportunity and for the next couple of summer months she was in our Qrs every evening playing with my kid son when I returned from Phy Dept via Harrys.

Yet another decade later, one midnight when I was coaching my son and his friend Dipu in Physics for their JEE, my son, in a moment of pique, placed his forefinger in the discharge path of a series LR circuit and asked me what happens if there is another inductor there. I gave him some vague answer, but that night I couldn't sleep, because that simple addition of an 'ideal' inductor was giving rise to a profound paradox: if I conserve current, energy is not conserved; and if I conserve energy, current is not conserved. What I thought was an interesting JEE problem was turning out to be nasty. And I found no way out for over a week; but I was enjoying the riddle though I couldn't solve it...typical symptom that there is a Paper in it that Physics Education would love.

One of those evenings there was a Fete in the backyard of the Technology Club and I escorted my wife there, although I never ate outside those days. It just happened that there came a moment when KV and I were thrown together without anyone else within earshot. And KV noticed that I was distracted and offered a penny for my thoughts. I then blurted out that I was unable to solve for more than a week a simple LR Decay circuit that my son invented. And KV jumped up and asked me what it was. I then saw that I put my foot in my mouth...I didn't want to tell him the problem for more reasons than one. One: it maybe too trivial for one who has dealt with circuit transients and Laplace, Fourier, and their kins' Transforms all his life. Two: the problem was giving me a lot of pleasure since it was a typical teaser. Three: if the problem turned out to be too tough for him to spell out the answer offhand, and if he works on it and gives me the solution using those wretched transforms, it will go out of the reach of my son, and I would be left with a big baby in my small lap.

So I demurred and changed the topic. But he was waiting after their khana for me and collared me again to state that simple problem that was foxing me for days on end. So I had to tell him that I would certainly seek his help if I decide finally that it was out of my reach. And after a month he caught me again in the cycle shed shared by Phy and EE and asked me if that problem got solved; and I had to say: "Not yet." That provoked him and he implored me to state it again and I dithered.

It took me six good months. Not that I was thinking about it day and night...I was too preoccupied with the cussed Lecture Notes I promised myself to compose...to prevent unwanted students attending my forthcoming Jumbo Classes. But it was there at the back of my (so-called) mind like the hum of the sea at the Vizagh beach-house I lived in for seven long years...when you are busy, you don't notice it...but the moment you try to relax, you hear it loud and clear and wonder how you could miss the infernal thing.

KV left me alone after a couple more attempts and finally one afternoon when I was sipping chai at Harrys, after a good six months, I saw what a fool I was to neglect the self-capacitance of the inserted inductor. You see, some paradoxes appear because you are so used to idealization in physics that you forget it. Here, no matter how ideal the inductor is, and however tiny its self-capacitance, it saves the situation from agony...and both current and energy (now electrical as well as magnetic) get conserved every moment.

Rest is simple...the one-loop LLR decay-circuit becomes two-loop series-parallel LCR oscillatory-decay circuit and you end up in a cubic equation that can always be solved by the Cardano's Method by inserting numbers...unlike linear and quadratic equations, the cubic devil in general has no closed-form solution. And the problem goes out of IIT JEE. I wanted to rig up such a circuit in our 4th Year Lab, but I never got around to it...it looked too trivial...there is this saying for it in our Telugu: "When it is not understood, it looks like Brahma Vidya (Supreme Knowledge); when it is mastered, it becomes Koosu Vidya (mere 'skill', like getting that yo-yo back in hand)."

One of those days, I was taking a class on History of Science and Technology for Research Scholars and noticed that one bright-eyed boy was enjoying it thoroughly. After the lecture, he ran after me and introduced himself as Mainak Sengupta and said he was always interested in Physics and used to make trips to the Dept of Physics at Kalyani University and met Prof Somnath Chakrabarty who told him that he did his M Sc Project under one gps (and left KGP with 4 Papers from it).

Mainak chose to do his compulsory one-sem Project under my guidance and published it as a Paper in Physics Education, Pune, where my son's LLR problem also appeared after gathering another couple of co-authors along the way.

And Mainak told me he was working for his Ph D under Prof KV and used to describe rapturously how MUCH he learned from him.

That sort of concludes happily the 'teacher-student-teacher-student' flowchart in academia like IIT KGP those four decades...


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