Er. Sanjeev Sinha's Physics Classes

17/06/2026

Re - NEET 2026

Some changes worth taking a note :

1. 15 minutes more time

2. 4 pages of rough sheets, 2 in front and 2 in back (in previous exams only 2 sheets were provided for rough work in the back)

3. Since wrist watches or any watch is not allowed inside the examination hall so “bell timings” are a crucial indicator about the time, which must be taken into account by the examinees.

*Last entry into the examination center at 1.30 pm (Long Bell)
*Distribution of Test Booklets at 1.50 pm (Single Bell)
*Seal of the test booklet to be broken/opened by the candidate and taking out the answer sheet at 1.55 pm (Double Bell)
*Commencement of examination at 2 pm (Long Bell)
*After 1hour ie at 3.00 pm (Single Bell)
*After 2hour ie at 4.00 pm (Single Bell)
*After 2 and half hour ie at 4.30 pm (Single Bell)
*Closing of room doors at 4.45/ 5.00 pm (Single Bell)
*Test concludes at 5.15pm (Long Bell)

The clouds and the silver linings -

- History tells that Re-Test papers are always difficult than the previous paper.
Lining - If it is difficult then it will be difficult for all, you are not the chosen one.
- What good can this extra 15 minutes do?
Lining - If you look at the questions in 1minute - 1question frame then you have got time equivalent of solving 15 questions, which can be extremely beneficial in solving the doubtful ones, without exceeding the regular time frame.

General advice - Between 1.30 pm and 1.50 pm ie for 20 minutes, you will be sitting idle in the examination hall. Within a minute or two you will start feeling lonely and alone at the same time. Don’t ever try to remember any formulae or revise any topic in you brain because it may confuse you more than comforting you. Jut take deep breaths and think about something positive, not related to your exams at all. May be, some good memories will help soothe your nerves.
You did it once so have no doubts about your capabilities of doing it twice! ALL THE BEST.

25/05/2026

Interesting question!

17/05/2026

It is hard to break students who find beauty in everything - even in pain! They transform scars into wisdom, struggles into strength and setbacks into comebacks! 😒

11/02/2026

OSM has been introduced in class 12 board exams from 2026. All concerned may take a note. Ignorance, many a times is NOT a bliss!

OSM (On-Screen Marking) :

OSM (On-Screen Marking) is a digital system introduced by CBSE for evaluating answer sheets. After the exams, student’s answer copies are to be scanned and uploaded to a secure online platform, where examiners will check them on a computer instead of on paper.

The system aims to :
• Reduce totalling and marking errors
• Ensure more uniform and transparent evaluation
• Speed up the checking process and result declaration

In OSM, students still write exams on paper, and teachers do the checking ; only the evaluation method becomes digital.

Writing tips for CBSE OSM system :

Under the On-Screen Marking (OSM) system, answer sheets are to be scanned and checked on computers. So, clarity and neat presentation are very important.
• Write in clear, slightly larger handwriting.
• Use dark blue or black pen.
• Avoid writing near the page edges.
• Present answers step-wise and box final answers in numericals.
• Underline keywords and use short, structured points.
• Keep diagrams neat and properly labeled.
• Avoid overwriting ; make clean corrections.
• Write correct question numbers and leave space between answers.

Main idea: Clear, neat, and well-structured answers are easier to read on screen and can help you score better.
It’s a thoughtful advice, nothing more…

05/10/2024

E x c l u s i v e l y for my students of +2 and competitions eyeing my public posts...
..The question which has made my life miserable now-a-days and am confronted with at almost all the places this poor teacher teaches is - "does light travel in a straight line or not?" How come it travels in a straight line in earlier classes and suddenly bends in class xii and beyond?? Many of the students suggested that 'light' might be on a high!
..Just think what made you believe that light travels in a straight line! In your earlier classes you were shown an experiment with three cardboards having pin holes in line, in them. A lighted candle was placed on one side and you were asked to observe the flame through the pin holes from the other side. When any of the cardboards were displaced even slightly, you were not able to see the flame. Hence you believed your teacher who said that light travelled in a straight line.
..In +2, you read two consecutive chapters in physics named "ray optics" which is based on rectilinear propagation of light and "wave optics" in which light travels as "wave" and can bend! Hence the confusion!
..Allow me to turn the pages of history of the world of physics which will give you the thrill of watching a fast paced movie and will answer your question too!
..Hardly anyone remembers the name "Descartes" who gave the "corpuscular model of light" and derived Snell's law from it. The model predicted that if the ray of light bends towards the normal after refraction then the speed of light will be greater in the second medium(!!). This model was developed by Newton who even wrote his famous book "OPTICKS" based on it and the corpuscular model is mostly attributed to Newton only! The name of Descartes is buried deep in history! Newton was the biggest star in the galaxy of scientists of his time and people simply believed, whatever he said! It took scientists like Huygen, Foucault, Young, Maxwell etc. years to even jointly challenge the "authority" of Newton on atleast this front. Huygen put forward his wave model of light and successfully explained the phenomenon of reflection and refraction. He also predicted that if after refraction the "wave" bends towards the normal then its speed will be less in the second medium! This was exactly opposite to what Newton said! Such was the authority and clout of Newton that this theory was outright rejected initially! But the story which started in 1637 finally ended in 1801. It took almost two centuries to make it "unsaid", what Newton once just "said"! Newton, was, is and will always remain the biggest superpower, the world of physics ever saw!
..Now, coming to the original question, kindly be informed that light has a wavelength of about half a micrometre in optical region. If it encounters an obstacle of about this size, it can bend around it and can be seen from other side. In the cardboard experiment, if you are able to move one of the cardboards by a micrometre or less, light will be able to diffract and the flame of the candle will still be seen.
..So, at the most you can say that light learns how to bend as it grows up!

15/08/2022

12/08/2022

Kind Attn. - Concerned students/parents

Just for infro! All slots full! Kindly don't recommend any one else to join the syllabus batch for CBSE. 🙏

ICSE/ISC syllabus batch(online) for 10th, +1 and +2 (Physics) will start shortly, which may kindly be noted.
Regards.

04/02/2022

E x c l u s i v e l y for aspiring engineers and doctors...

"Faith" doesn't have any space for "possibilities". Doubtful persons have 'shaky' faith. "Eagle" always fly alone and has the faith that he won't get lost. So, my dears ; have "firm" faith in your capabilities and continue doing what you are doing best at. Life doesnot give you "one" chance! On the contrary, it goes on throwing at you chances after chances till you grab one of your choice. Competition is "tough" but that cannot undermine your "toughness". You "planned" it, you are "preparing" for it and the time of "ex*****on" is slowly but surely nearing by. Every "second" is at premium so give it your best shot without having even the slightest of doubts about the outcome. No "engine" have got 100% efficiency apart from an "ideal" engine which exists in theories only. Take out some time for your favourite "music" too...it will sooth you. The count down has begun and the world of engineers and doctors are awating patiently to applaud your arrival in their esteemed family. Your "body" will slowly start living in the 'pre-historic jungles' and fight the 'stress' on its own similar to a small 'cut' healing on its own. Beware, don't get lost in the jungle of intellectual exercise!
All the best... 🙂

13/08/2021

𝐎𝐍 𝐃𝐄𝐌𝐀𝐍𝐃...
𝘖𝘯𝘭𝘪𝘯𝘦 𝘤𝘰𝘢𝘤𝘩𝘪𝘯𝘨 𝘤𝘭𝘢𝘴𝘴𝘦𝘴 𝘧𝘰𝘳 𝘌𝘯𝘨𝘪𝘯𝘦𝘦𝘳𝘪𝘯𝘨 𝘗𝘩𝘺𝘴𝘪𝘤𝘴/𝘌𝘯𝘨𝘪𝘯𝘦𝘦𝘳𝘪𝘯𝘨 𝘔𝘢𝘵𝘩𝘴 𝘧𝘰𝘳 𝘦𝘯𝘨𝘪𝘯𝘦𝘦𝘳𝘪𝘯𝘨 𝘴𝘵𝘶𝘥𝘦𝘯𝘵𝘴 𝘢𝘯𝘥 𝘖𝘱𝘦𝘳𝘢𝘵𝘪𝘰𝘯𝘴 𝘙𝘦𝘴𝘦𝘢𝘳𝘤𝘩 𝘧𝘰𝘳 𝘦𝘯𝘨𝘪𝘯𝘦𝘦𝘳𝘪𝘯𝘨/𝘮𝘢𝘯𝘢𝘨𝘦𝘮𝘦𝘯𝘵 𝘴𝘵𝘶𝘥𝘦𝘯𝘵𝘴 𝘢𝘯𝘥 𝘰𝘵𝘩𝘦𝘳 𝘱𝘳𝘰𝘧𝘦𝘴𝘴𝘪𝘰𝘯𝘢𝘭 𝘤𝘰𝘶𝘳𝘴𝘦𝘴 𝘸𝘪𝘭𝘭 𝘵𝘦𝘯𝘵𝘢𝘵𝘪𝘷𝘦𝘭𝘺 𝘴𝘵𝘢𝘳𝘵 𝘧𝘳𝘰𝘮 25𝘵𝘩 𝘈𝘶𝘨𝘶𝘴𝘵'2021.
𝗔𝗻𝘆 𝗾𝘂𝗲𝗿𝗶𝗲𝘀 𝗺𝗮𝘆 𝗸𝗶𝗻𝗱𝗹𝘆 𝗯𝗲 𝗳𝗼𝗿𝘄𝗮𝗿𝗱𝗲𝗱 𝘁𝗼 +𝟵𝟭 𝟴𝟳𝟬𝟵𝟮𝟰𝟴𝟴𝟲𝟵.