May19

The Mindset Behind IIT JEE Advanced AIR 56, IJSO Gold, and World Rank 10 in SIN: Vasu Vijay’s Extraordinary Journey

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Very few academic journeys reflect excellence across so many of the world’s most prestigious examinations and Olympiads at such a young age. From securing an extraordinary AIR 56 in IIT-JEE Advanced, to winning a Gold Medal with International Rank 8 at the International Junior Science Olympiad (IJSO) 2022 in Bogotá, Colombia, to achieving International Rank 10 along with Distinction in the prestigious Sir Isaac Newton (SIN) Exam conducted by the University of Waterloo, Vasu Vijay’s accomplishments stand as a remarkable testament to intellectual depth, discipline, and conceptual mastery.

What makes his story especially meaningful to me, however, is not merely the scale of these achievements, but the transformation behind them.

As Vasu himself shares in this testimonial, there was a time when Physics felt difficult and unintuitive to him. Over the years, through a learning approach centered around intuition, conceptual understanding, analytical thinking, and scientific imagination, he gradually developed not only mastery over the subject, but also a genuine love for it.

His words beautifully reflect a philosophy I have always believed in deeply — that true excellence in Physics does not emerge from memorizing formulas or mechanically solving thousands of problems, but from learning how to think clearly, understand concepts fundamentally, and approach challenges with calmness and intelligence.

One of the most touching parts of Vasu’s testimonial is his gratitude toward the way he was taught to approach both Physics and examinations themselves — not with fear or pressure, but with curiosity, strategy, and confidence. To know that this mindset contributed meaningfully to his Olympiad journey, his international success, and his IIT-JEE performance is profoundly fulfilling as a teacher.

Vasu’s journey is not merely a story of ranks and medals. It is a story of transformation — from confusion to clarity, from hesitation to confidence, and from learning formulas to truly understanding the beauty of Physics.

I feel immensely proud to have been part of his journey and deeply grateful for the sincerity and warmth with which he has expressed his appreciation.

Respected Devansh Sir,

I remember that at the beginning of Class 9, Physics was the subject I struggled with the most. Even the basic concepts often felt unclear to me, and I never really enjoyed studying the subject. However, the way you taught Physics completely changed how I viewed it. Your emphasis on intuition and conceptual understanding helped me develop genuine interest in the subject.

What impacted me the most was that your teaching was never limited to memorizing formulas or blindly applying methods. Instead, you always encouraged us to understand the idea behind every concept and every question. Because of this, whenever I now encounter a Physics problem, my first instinct is to understand the concept deeply before attempting to solve it. The questions discussed in class were themselves more than sufficient to develop a strong understanding, without the need to solve hundreds of questions from multiple books.

Apart from academics, your guidance regarding examination pressure and mindset also helped me immensely. I still remember your idea of treating an exam like a puzzle, where the objective is to optimize marks, calmly and intelligently. That approach proved to be extremely effective for me and positively influenced my performance in every major examination thereafter.

This way of learning and approaching Physics helped me throughout my entire Junior Science Olympiad journey, from NSEJS and INJSO to the OCSC selection camp at HBCSE, eventually culminating in a Gold Medal and an International Rank 8 in IJSO 2022 held in Bogotá, Colombia. The same approach and mindset later continued to help me in other examinations as well, including JEE Advanced, where I secured AIR 56, and the Sir Isaac Newton (SIN) Exam, where I secured an International Rank 10 along with a Distinction.

I will always remain grateful to you not just for teaching Physics so beautifully, but also for changing the way I approach learning and problem solving as a whole. Thank you for making Physics so intuitive and enjoyable for me!

Vasu Vijay

May17

Carnot Engine: Proof of Carnot Theorem…

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“It is impossible for any heat engine to be more efficient than a Carnot engine when operating between two given temperatures”.

The Carnot engine is a conceptual engine that achieves the most efficient conversion of heat to work permitted by Kelvin’s statement. In general, efficiency is defined as the ratio of work out to heat in:

For a Carnot engine, the efficiency is found in terms of the temperature of the reservoirs the engine operates between:

Carnot’s Theorem

It is impossible for any heat engine to be more efficient than a Carnot engine when operating between two given temperatures:

Consider a heat engine drawing heat Q1 from a heat reservoir at temperature T1​, delivering work W and dumping heat Q2​ into a heat sink at temperature T2.

The heat engine operates in cycles, that is, it takes in heat Q1, does work W, dumps heat Q2, and in the end returns back to its original unchanged state.

Consider the net change in entropy ΔS of the universe:

The heat reservoir releases a heat Q1 at a constant temperature T1. Thus the change in its entropy is

The heat sink accepts heat Q2 at a constant temperature T2. Thus the change in its entropy is

Thus the net change in entropy of the universe is

Using the second law of thermodynamics, ΔS≥0, which implies

Since the left-hand side represents the efficiency of the given heat engine (η) and the right-hand side is the efficiency of a Carnot engine,

Hence proved!

May17

Pressure is Isotopic: It Has No Preferred Direction

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Pressure Is Isotropic

Why Pressure in a Fluid Acts Equally in All Directions

One of the most fundamental results in fluid mechanics is:

At a given point inside a stationary fluid, pressure acts equally in all directions.

This property is called the isotropy of pressure.

At first glance, the statement appears intuitive. Yet it emerges from a deep physical requirement: a fluid at rest cannot sustain shear stress.

The Core Physical Idea

Unlike solids, fluids cannot resist continuous tangential deformation. If unequal directional stresses existed at a point inside a stationary fluid, the fluid element would experience a net turning or shearing effect.

The element would then deform and begin to flow.

But a stationary fluid, by definition, is in equilibrium.

Therefore:

No directional imbalance can exist inside a fluid at rest.

Pressure must therefore act equally in every direction.

The Conceptual Proof

Consider an extremely small fluid element inside a liquid at rest.

Suppose pressure along one direction were greater than pressure along another direction.

The larger pressure would produce a greater force on one face of the element, generating an unbalanced shear tendency. Since fluids cannot sustain shear stress in static equilibrium, motion would immediately begin.

This contradicts the assumption that the fluid is stationary.

Hence the only possible equilibrium condition is:

Thus, pressure at a point in a static fluid is isotropic.

An Important Consequence

Because pressure has no preferred direction:

  • fluids exert force perpendicular to surfaces,
  • Pascal’s law becomes possible,
  • and hydraulic systems function efficiently.

From ocean depths to hydraulic lifts, isotropic pressure governs the behavior of fluids everywhere.

Final Conclusion

Pressure in a stationary fluid is isotropic because any directional inequality in pressure would create shear forces and destroy equilibrium. Nature preserves stillness inside fluids by ensuring perfect directional balance.

May13

Gratitude from IIT JEE Topper AIR 1 – Rajit Gupta to Devansh Sir

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Some journeys begin with talent. Others begin with the right guidance at the right time.

Rajit Gupta first joined my NSEJS batch as a young student in 9th grade with curiosity, sincerity, and a willingness to learn deeply. Over the years, that curiosity evolved into extraordinary achievement — culminating in an exceptional academic journey that includes AIR 1 in Joint Entrance Examination – Advanced, 100 percentile in JEE Mains, selection in multiple prestigious Olympiad camps, qualification for International Physics Olympiad, and selection for APhO twice.

What makes Rajit’s journey especially meaningful to me is not only the scale of his achievements, but the depth of understanding and intellectual maturity he developed along the way. His testimonial beautifully reflects the philosophy I have always believed in — that true Physics education is not about memorization, but about intuition, clarity, imagination, and genuine curiosity.

I am deeply proud of Rajit and grateful to have witnessed his remarkable journey from a young Olympiad student to one of the finest performers in the country.

Respected Devansh Sir,

I am Rajit Gupta. I was your student in NSEJS batch in 9th grade. This year I appeared in JEE and I have got Rank 1 in JEE Advanced, 100 Percentile in JEE Mains, and very good scores in NSEP and NSEA.

I wish to express my deepest gratitude for the immense impact you have had on my journey.

When I started learning physics in your classes, it was completely new to me. But instead of just making me memorize concepts, you motivated me to truly understand them. Your guidance not only helped me build strong intuition but also sparked a genuine interest in the subject.

What sets you apart is the effort and dedication you put into each of your students. Your well-thought-out resources, insightful suggestions, and constant encouragement played a crucial role in my growth. Thanks to your support, I was selected for the Junior Science OCSC, Astronomy OCSC and later for the Physics OCSC twice. I qualified for IPhO this year and also got selected for APhO two times (although I wasn’t able to attend the event this year due to my JEE).

Looking back, I realize that without the strong foundation you gave me, none of this would have been possible. You gave me the perfect kickstart, and for that, I will always be grateful.

Thank you very much, Sir!

Best regards,
Rajit Gupta

May13

“Physics Started Making Sense” — A Heartfelt IIT Bombay Student Testimonial

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Sometimes, even a few months of the right guidance can completely transform a student’s confidence and way of thinking. Palak Sanadhya joined my classes only a short time before JEE Advanced, yet her sincerity, hard work, and deep commitment toward conceptual understanding helped her secure admission to Indian Institute of Technology Bombay in Chemical Engineering.

What makes her testimonial especially meaningful to me is that it reflects the very philosophy with which I teach Physics — not as a collection of formulas to memorize, but as a subject to be visualized, understood intuitively, and appreciated deeply. I am grateful to have played a small role in her remarkable journey.

Securing admission to Chemical Engineering at Indian Institute of Technology Bombay after clearing one of the most competitive examinations in the country was a dream come true for me. And although I studied under Mr. Devansh Mittal for only around three months before JEE Advanced, the impact of his teaching during that short period was truly remarkable.

What immediately stood out to me in his classes was the way he approached Physics — not as a subject to be memorized, but as something to be deeply understood and mentally visualized. In an environment where students often focus only on speed and formulas, his teaching emphasized imagination, intuition, and conceptual clarity.

Whether it was Mechanics, Thermodynamics, Waves & Oscillations, Electrodynamics, Optics, or Modern Physics, he explained every topic with extraordinary precision and simplicity. Even concepts that had previously felt confusing became intuitive after his explanations. His ability to connect physical understanding with mathematical problem-solving made a tremendous difference in my preparation.

One of the most unique aspects of his teaching was his belief, inspired by Albert Einstein, that imagination and intuition are just as important as logic in learning Physics. Instead of encouraging rote methods, he trained us to think independently and understand the deeper meaning behind every concept. That approach not only improved my problem-solving ability, but also gave me confidence while attempting challenging JEE Advanced questions.

Beyond academics, I was deeply touched by the sincerity and honesty with which he guided his students. He genuinely cared about our progress, regularly communicated with parents, and ensured that students remained disciplined, motivated, and mentally focused during such an important phase of preparation.

Despite the limited time I spent under his mentorship, his guidance had a lasting impact on my understanding of Physics and my confidence as a student.

Mr. Devansh Mittal is far more than an excellent teacher — he is a mentor who inspires students to think deeply, learn sincerely, and believe in their own potential.

I will always remain grateful for his support and guidance during one of the most important phases of my academic journey.

— Palak Sanadhya

May13

“I Have Not Seen Such High-Quality Lectures Before”: An IIT Delhi Professor’s Remarkable Testimonial

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There are moments in a teacher’s journey that become deeply meaningful — not merely because of praise, but because of the source from which that appreciation comes.

Receiving a heartfelt testimonial from Prof. Saif Khan Mohammed of Indian Institute of Technology Delhi was one such moment for me.

Prof. Saif is not only a distinguished academician from the Department of Electrical Engineering at IIT Delhi, but also someone who himself secured an under-100 rank in IIT-JEE during his student years. His deep understanding of Physics, analytical thinking, and exposure to high-level technical education make his words especially valuable and humbling.

What touched me most was not simply his appreciation of my lectures, but his recognition of the philosophy behind my teaching — beginning from first principles, developing intuition step by step, and helping students gradually build the confidence to solve highly challenging problems, including advanced problems from the legendary book by I. E. Irodov.

As educators, we often strive not merely to teach formulas, but to cultivate curiosity, clarity of thought, and genuine understanding. To know that these efforts resonated with a respected IIT Delhi professor and benefited his daughter deeply is something I will always cherish.

I am sharing his words below with immense gratitude and humility.

Dear Shri Devansh

I am Prof. Saif Khan Mohammed, Dept. Electrical Engineering l.I.T. Delhi. My daughter is enrolled in your online course. I have been personally viewing your physics video lectures and I must say that I have not seen such high quality lectures before. My daughter has seen other online lectures, but none of them are as good as yours. After seeing your lectures she was able to solve difficult problems in Mechanics from the book by I. E. Irodov. The way you start any topic from basics and gradually increase complexity is what makes it easy for students to learn physics with so much ease. I thank you for your great contribution to education and I am sure you will make even greater contribution in the years to come.

Prof. Saif

IIT Delhi

—

Prof. Saif is a learned professor at IIT Delhi. He himself had under 100 Rank in IIT-JEE when he appeared into it.

https://iitd.irins.org/profile/70117

May9

MIT, Stanford, Oxford & Beyond — Rudra Pethani’s Gratitude for Devansh Sir

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Rudra Pethani is one of the most exceptional young students I have had the privilege to teach. His remarkable journey reflects not only extraordinary intelligence and hard work, but also deep curiosity, discipline, and a genuine passion for learning.

Rudra represented India at the 20th International Junior Science Olympiad (IJSO) held in Thailand and brought immense pride to the nation by winning a Gold Medal. Over the years, he has consistently demonstrated outstanding academic excellence and an exceptional ability to think deeply and intuitively about science and problem solving.

Today, his achievements have earned him acceptance into some of the finest universities in the world — including MIT, Stanford University, Oxford University, and Imperial College London — an accomplishment that very few students across the globe achieve.

What makes Rudra truly special is not only his brilliance, but also his humility, sincerity, and relentless desire to understand concepts at their deepest level.

Below is a heartfelt testimonial written by Rudra about his learning journey and experience with my physics mentorship.

My name is Rudra Pethani, and I am studying in Allen Career Institute.  

I came in contact with Devansh Sir in January 2024 for the INJSO Online Workshop, and I have been his student ever since. He has a completely different and unique approach to physics that I had never seen before. His clear and concise manner of speaking makes each and every student understand what he is trying to convey to us. Moreover, his systematic and methodical approach towards problem solving and concept building has really helped me get a strong grasp on the entirety of physics. The emphasis given to intuitive learning of all the various topics has helped me gain confidence and given me the ability to solve even the toughest of problems. 

I would like to thank Devansh Sir for imparting his vast knowledge to me. Without his guidance, I do not think I would have been able to get this wonderful achievement. 

Apr5

The Intouchables: A Humorous Dive into a Sparkling Friendship.

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The Intouchables, originally a French Film, a winner of 38 “Best Foreign Language Film award”, a movie based on true events, an intricately fabricated profound work of art, surely is a medley of sparkling humor, subtle emotions, and a deep dive into nature of human relationships. It’s truly an irresistible delight for the connoisseurs of the finest cinematic experience.

The movie revolves around the two main characters — Philippe and Driss.

Philippe, played by François Cluzet, is a millionaire, and handsome aristocrat who is deep inside a free-spirited, fast-paced, adventure-loving, energetic and humor seeking person, meets an accident while Paragliding and happens to become a quadriplegic, a person who is paralyzed right from the base of his neck to the last toe on his foot. Philippe’s life, now due to the helplessness given by quadriplegia, is limited to mostly the walls of his mansion, the routine care of doctors and caretakers and the pity of the rest of the world. In summary, he is living hell in the midst of his affluence.

Due to the consistent exposure of pity, dependence, and helplessness, he happens to devote his life to intellectual activities, arts, music, drama, literary events, and epistolary relationships (distant conversations with a person through letters only). There is a lot of insipidity in his life. His true innate energetic and adventure-loving nature is now lost, which he has now accepted as his fate.

He happens to meet and finally hires Driss, Omar Sy, as his caregiver, who is totally opposite of what Phillipe is from the outside. Driss is black west African. He is impulsive, he is uncultured, raw, reckless, violent, free-spirited, fast-paced, humorous and aimless person. He comes from one of Paris’s poor, suburban high-rise ghettoes, and is seeking some money. He has also been recent to jail for 6 months for robbing a Jewelry store.

In spite of two of them being so different, what binds them together is their total love for honesty of character, sense of humor and contempt for stuffy hypocrisy. And, most importantly, Driss is actually the outward raw and honest manifestation of the innate character of Phillipe. What Phillipe likes about Driss the most is, he treats him like a normal human being with all his arms and legs, he doesn’t pity him, he doesn’t make him realize of quadriplegia all the time and rather he makes him feel good, makes him feel lively again and makes him laugh again. The laughter which was missing in Phillipe’s life for ages. This becomes the greatest binding force in their relation.

Philipe shares that he lost his loving wife the same time he got quadriplegia and his true disability is not having to be in a wheelchair, but it’s having to be without his wife.

Driss brings taste in Phillipe’s insipid life. They both learn and grow with each other. Phillipe learns to enjoy the daily life mundane things apart from his literary and intense interests and at the same time, Driss gets more responsible and civilized in the journey!

Both of them have performed phenomenally. Their every action and expression is praiseworthy. It’s an epitome of a true and deep friendship that grips, holds and takes the spectator on an around 2 hours long journey of humor and subtle emotions.

An inevitably must watch.

My Rating: 4.5/5.

Jan17

Chapaak: The Splash of Acid!

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“No death, no doom, no anguish can arouse the surpassing despair which flows from a loss of identity” and this is what an acid attack does to a person. Even the spectators of the movie “Chapaak” begin to feel that death is better than surviving an acid attack. I watched this movie with my parents and they were terrified of being the parents of a daughter.

“Chapaak” is a very good cinematic depiction of such a Spine-Chilling and Blood-Curdling issue. The film is based on a true story of Laxmi Agarwal who suffered from an acid attack in 2005.

The movie successfully touches the core issues behind such a horrifying act i.e. a conglomeration of Patriarchy, Misogyny, Hate, and Violent Tendencies. The following dialogue in the movie summarizes the “Hate” aspect of it. It says “Acid first dissolves in the mind and then it comes in the hand”.

While keeping the issue of “Acid Attacks” as the main theme, the movie rightly and meticulously also shows the inadequacy in jurisprudence as well.

The profoundly inspiring part of the movie is when after having suffered a terrible acid-attack the protagonist, Malti, played by Deepika Padukone, recuperates physically and psychologically and is ready to face the world with not only courage, but also with love and humility. It reflects in the following statement.

The kind of severe assault, Malti suffered with, can make anybody very hard-boiled, cynical, and distrustful, but as the movie progresses, the way Malti responds to various situations and the way she leads her life makes the spectator, fall in love with the beautiful character of Malti, behind the Acid Burnt Face.

If you have ever felt excruciating physical pain in your life, then you are bound to relate to the piercing cries of Malti, played by Deepika Padukone, who also co-produces the film with Gulzar. Towards the climax, just when you are beginning to relax your shoulders, the movie shakes you like a leaf, by portraying yet another gruesome acid-attack incident. This denial of catharsis is what gives Chhapaak its uneasy and poignant effect.

A must watch.

My rating: 4 / 5.

                              Laxmi Agrawal before and after Acid Attack in 2005.

Further Explorations

  1. TED Talk by Laxmi Agrawal “He Threw acid on my face, but not on my dreams”.
  2. Loving The Faceless: 26-Year-Old Champions Acid Attack Victims | Champions For Change | CNA Insider
  3. Acid Attack Victims
Nov22

The Bell-Shaped Curve: A Common Pattern in Nature…

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Following is Maxwell’s Distribution of Velocity Curve, in Kinetic Theory of Gases.

1*A2YXBk8eYVOKi5FMFKn13A

Following is the Wein’s Displacement Law, in Thermal Radiations.

Following is the Distribution of Kinetic Energy of Beta Particles in Radioactive Decays.

Following is the distribution of Intelligence among people in general.

Following is the distribution of Salaries in various countries among people.

Do you notice a pattern here?

All of them are Bell-Shaped curves. All the graphs shown above come from completely different fields of studies and still, they share a similar distribution pattern. Isn’t it strange and amazing? Doesn’t that point to some hidden mysteries of nature?

The bell-shaped curve is a common feature of nature and psychology. In statistics it is called a “Normal Distribution” and it is given a lot of importance in statistics and probabilistic distributions.

What is a Normal Distribution in Statistics?

A normal distribution has a bell-shaped curve and is symmetrical around its center, so the right side of the center is a mirror image of the left side.

Most of the continuous data values in a normal distribution tend to cluster around the mean, and the further a value is from the mean, the less likely it is to occur. The tails are asymptotic, which means that they approach but never quite meet the horizon (i.e. x-axis).

For a perfectly normal distribution the mean, median and mode will be the same value, visually represented by the peak of the curve.

The normal distribution is often called the bell curve because the graph of its probability density looks like a bell. It is also known as called Gaussian distribution, after the German mathematician Carl Gauss who first described it.

Why is the normal distribution important?

The bell-shaped curve is a common feature of nature and psychology

The normal distribution is the most important probability distribution in statistics because many continuous data in nature and psychology displays this bell-shaped curve when compiled and graphed.

For example, if we randomly sampled 100 individuals we would expect to see a normal distribution frequency curve for many continuous variables, such as IQ, height, weight and blood pressure.

Parametric significance tests require a normal distribution of the samples’ data points. The most powerful (parametric) statistical tests used by psychologists require data to be normally distributed. If the data does not resemble a bell curve researchers may have to use a less powerful type of statistical test, called non-parametric statistics.

The normal distribution is so important in statistics that statisticians have written down books and have developed several theorems on just this single idea! One of the epitome of such theorems is Central Limit Theorem, which summarizes the idea discussed so far.

Later, I posted the same question on Physics Stack Exchange too, to receive more knowledge on the subject and yes it resulted positively. Following is the conversation.

https://physics.stackexchange.com/questions/521843/why-most-distribution-curves-are-bell-shaped-is-there-any-physical-law-that-lea

Further Readings and explorations.
1. The Normal Distribution: Crash Course Statistics #19
2. What is a Normal Distribution in Statistics?
3. Why is Normal Distribution Bell Shaped?
4. The Normal Distribution and the 68–95–99.7 Rule (5.2)
5. Why do airlines sell too many tickets? — Nina Klietsch