Riya Singh 12th Sample

Acid tests. Sodium bicarbonate: carboxylic acids give brisk effervescence of CO2, phenols don't (phenol is weaker than carbonic acid). So benzoic acid vs phenol: use NaHCO3. Neutral $FeCl_3$ gives violet with phenol, not with benzoic acid (benzoic acid gives a buff-coloured precipitate with it, but NEET won't ask that). Special case: formic acid, which has an aldehyde-like H, reduces Tollens' and Fehling's reagents, unlike other carboxylic acids.

4d ago

I'm a poetry person so take this as feeling and not as maths: a limit is a promise you can keep without ever arriving. "Within δ of a" is how close you're willing to stand, and the definition says: however near the answer asks me to be, I can always get there. And you never have to touch the point. It's the closest thing maths has to a love letter.

4d ago

Ishaan, a longer post isn't more value, it's just longer. Long posts work only if every part earns its place. Teachers grade language one way, readers on a blog behave differently. Try writing the first one at 500 words and see if you miss the rest.

4d ago

Number 3 is everything. "The Thursday curry has a texture I can only describe as regret" made me laugh out loud in a quiet room. For poetry it's the same rule, the concrete image always beats the big abstract word.

4d ago

C-R-Q for 2-3-4, that's the kind of mnemonic I can keep. thanks lakshmi!

5d ago

yes exactly. the phone averages the scene and picks something in the middle, and the sky loses. you have to tell it what matters

5d ago

Biggest culprit is almost certainly the time of day. Midday sun is flat and harsh: the sky blows out to white and colours look washed. Same view at 7am or 5pm will look completely different, because the sun is lower and the light is warmer and has direction. If you can't change the time, you need to work around it: look for shade, side light, anything that adds shape. For the sky turning white: tap on the brightest part of the sky, then slide the exposure down a bit so the sky keeps its blue. The foreground gets darker but you can lift it a little in editing. It's easier to rescue shadows than blown highlights.

5d ago

About Delhi, think about where the centre of the orbit has to be. The only force on the satellite is gravity, and it points to the centre of the Earth, so the orbit's plane has to pass through the Earth's centre. Any circle in such a plane that stays above one point must be above the equator, because the equator is the only latitude circle whose plane passes through the Earth's centre. A satellite parked over Delhi would need a force toward the Earth's axis, not toward the centre, and nobody is providing that. So no geostationary over Delhi, but the equatorial one can still "see" India, that's how the TV dish works.

6d ago

Lakshmi, take it. And do something small that's yours on that day. ❤️

6d ago

Write about it too. I think art and science are the same urge, "look carefully and then make it clear to someone else." Whatever you decide, don't kill the drawing. A hobby you keep alive can become a career later, or just a lifelong friend.

7d ago

MEERA. that's so good. this is exactly the moment.

9d ago

thank you both. the "spreads everywhere but the polar spring does the damage" bit makes so much more sense than my first guess. I'm changing my poem's line from "a hole in the sky" to "a thinning" 🌙

9d ago

Speed vs velocity again, as always. "A force perpendicular to v changes direction not speed". Writing it on a card. Thanks everyone, this one has a good ending after all.

9d ago

okay that's the explanation I was missing for years. thank you arjun. I'll try the key at 10 and 45 degrees and see if I can see the difference.

9d ago

thank you zoya. Yes, the "step back" part is what I'm still learning from her.

9d ago

Acid rain eats marble too, the Taj Mahal is the usual NCERT example: $CaCO_3 + H_2SO_4 \rightarrow CaSO_4 + H_2O + CO_2$. Calcium sulphate is more soluble than the carbonate, so the surface slowly dissolves and the white marble gets damaged. I find the image sad, a poem in itself.

9d ago

Your HGP facts are on track. NCERT also says 99.9% of nucleotide bases are exactly the same in all people, and that functions are unknown for over half of the discovered genes. SNPs (single nucleotide polymorphisms) were found at about 1.4 million locations, useful for tracing history and finding disease associated sequences. One more: repetitive sequences make up very large portions of the human genome.

9d ago

Phase difference, I like to picture it as a hill moving. A point further along $x$ sees the same crest *later*. Over one full wavelength $\lambda$ the phase changes by $2\pi$, so $$\Delta\phi = k\,\Delta x = \frac{2\pi}{\lambda}\Delta x$$ For your wave, $\lambda \approx 1.26$ m. Two points $0.314$ m apart, a quarter of a wavelength, differ in phase by $\pi/2$. For the same point at two different times, $\Delta\phi = \omega\,\Delta t$. Time and space give the same idea in two units.

10d ago

thank you, now I can write one clean paragraph. the loop even has a rhythm to it, which is probably why I wrote a poem 🙂

13d ago

Sara, I read them on bad days. It's like a letter from a version of me who was doing okay. Highly recommend 🙂

14d ago

Lakshmi, I'm glad. Quiet people see a lot. I hope you also write more, I like reading what you write.

15d ago

Thank you Zoya 🙂 that means a lot, especially from you.

15d ago

"Stood in a saree thinking about the nitrogen cycle" is going in my poem notebook. Thank you for writing this, nisha. Also yes, I cried at the slideshow. Stupid photos.

15d ago

This is gorgeous. My nani says "rooh khush ho gayi" when food is really good, literally "the soul got happy". English has no sentence that does that job. Some feelings only come in one language.

16d ago

"a long train journey when you pass the third hour" is the most accurate line about waiting I've read. Sending you a lot of warm tea

16d ago

"staring harder is just sitting" is going on my wall. there's a kind of stuck that feels like standing in front of a locked door with the key in your pocket, except you don't know that you have a pocket. thank you for writing about the log, I think I'd have to start one too, for essays 😂

18d ago

"the parent becomes two daughters": that's the line I was missing, thank you zoya. Writing it somewhere a poem can find it.

19d ago

Tetany always confused me too, because calcium helps muscles contract, so I thought tetany = "too much Ca²⁺ = too much contraction". I like having a logical reason so I remembered it like that. I think it's the reverse for osteoporosis, where Ca²⁺ is low in the bones. Is this right?

19d ago

I think of it as a bank balance. $\Delta U$ is the balance. $q$ and $w$ are deposits (positive) or withdrawals (negative) from the system's point of view. Whatever the convention, the system's own bank statement uses its own signs. Not the most scientific but it helped me stop panicking.

20d ago

the line about "you are looking at one result in the dark" is going in my notebook. It's written the way my head feels at night 🌙

20d ago