Know which questions are eating your marks.
Free speed training on 70 JEE questions across 25 topics — Chemistry, Physics, Math. JEE Main grading (+4 / −1). No account needed to train.
Stop Memorizing Tables: Crack JEE Spectroscopy in 20 Seconds
Find a topic or question
25 topics · 70 questions · hack sheets & concept labs. No sign-in needed.
Speed is a subject.
JEE isn't only about knowing — it's about time economics. This trainer measures what every solve costs: Time-Efficiency Ratio (TER), Topper-Velocity zones, time leaks, and guess-vs-concept diagnostics.
Pick your exam — tap a card and your run starts immediately.
Your velocity map
Greed = wrong answer with a first tap faster than the question's guess threshold (a guess-flag, not a judgement). Concept-gap = wrong with a genuine attempt.
Your exam-economics card
Share it with your study group — this is what a test series never tells you.
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How the trainer works
Pick a set, beat the clock, and learn what every solve costs you. Everything below describes features that are live right now.
Speed runs
Speed-Run (JEE Main): single-correct questions, big timer, streaks. Marking +4 / −1 — beat the hack pace shown on each question.
Tactical Mode (JEE Advanced): multi-correct checkboxes with a risk panel before you submit. Marking +4 if everything you ticked is right, +1 per correct option for a partial attempt, −2 if anything you ticked is wrong. Untick what you are unsure of. No account needed — training is fully anonymous.
The trainer's bank is a growing set of 70+ JEE-style problems across topics (and counting). A full JEE Main paper presents 90 questions of which 75 are attempted — topic sets are training units, not full papers.
The four zones
TER (Time-Efficiency Ratio) = target time ÷ your time. After a run, every attempt lands in one zone:
- Topper — correct and fast. Topper velocity. Hold the pace.
- Time-Trap — correct but slow. Hesitation is the leak, not the concept.
- Lucky Guess — fast and wrong. Rushed first taps burn negative marks.
- Dead Weight — slow and wrong. A concept gap: re-learn, don't just retry.
Time Leak = time leaked on correct-but-slow solves. Greed Loss = marks lost on rushed wrong answers. Your velocity profile is your most common zone across the run.
Hack Sheets
One-page pattern tables you can print and stick on the wall — one for every Chemistry topic: Spectroscopy, Coordination Compounds, Reaction Mechanisms, Chemical Bonding, Electrochemistry, Organic Chemistry, Chemical Kinetics, Thermodynamics, Periodic Trends. The Print / Save PDF button produces a clean black-on-white sheet, nothing else.
Concept Lab
Small interactive demos that build the pattern yourself instead of memorizing it — one lab per Chemistry topic: flip the bromine coin, split the d-orbitals, call the mechanism, build a galvanic cell, and more.
Share Card
After a run, your diagnostic card appears — net score, greed loss, time traps, and your velocity profile. Download it as a PNG or share it straight to a friend.
No passwords here
There is no password. Enter your email and we send you a sign-in link — good for 30 minutes, single use. Click the link, then tap Finish signing in on the page to complete your login. Each link works on its own — requesting a new one doesn't cancel an earlier link. Can't find it? Check spam.
Sign-in is only needed for Cohort and Admin. Training needs no account.
When you're signed in you'll see a role next to your name: Student (training), Cohort (you're in a cohort — you get the velocity map), or Admin (institute admins).
Cohorts
Create a cohort or join your institute's with its code. The cohort dashboard shows the batch's velocity, greed %, concept gaps, time traps, a per-attempt scatter of time vs marks, per-topic heat, and a leaderboard on net exam economics.
Admin portal
Institute admins can roster students into a batch by pasting CSV or JSON, then watch batch telemetry — rostered vs claimed vs active students, completion, and risk flags — for their own institute's cohorts only.
What we track
First-party analytics only: per-attempt timing and aggregate counts, no keystroke capture, no ad trackers. Many of our users are students, so we keep it minimal on purpose.
Stuck?
- Link expired — request a fresh one; links are good for 30 minutes.
- Signed in but asked to sign in — sign out once, sign back in once. Still stuck, contact us below.
- Seeing a STAGING banner — you're in the test environment, not the live app. Use jee.buildfamiliar.com.
Questions? Message us from the TopTrendingTopics channel's About page on YouTube.
Ask the helper
A rules-based assistant that answers from these same help docs — no AI guessing, and your questions are never stored. Anything it can't answer is saved for the humans to teach it.
Ask the helper
Answers come from the app's own help docs — a rules engine, not AI. It can also check your sign-in state and the app's status live. Your questions are never stored in your browser; ones it can't answer are logged (text only) so the humans can teach it.
Sign in
One sign-in for everything: save your progress, join your institute's cohort, or manage batches as an institute admin. Training itself needs no account.
The bromine coin flip
Bromine comes in two flavors — ⁷⁹Br and ⁸¹Br — about 50/50 each. Flip a pair of bromine coins 40 times and watch the mass-spec peaks build themselves:
Two bromines give combinations (79,79), (79,81)/(81,79), (81,81) → peaks at M, M+2, M+4 in ratio 1 : 2 : 1. You don't memorize the table — you just built it. Same idea for chlorine: ³⁵Cl : ³⁷Cl is 3 : 1, so two chlorines square it → 9 : 6 : 1.
Fold the benzene
p-Dibromobenzene has a centre of symmetry: all four ring protons live identical lives → one singlet (4H) near δ 7.5. The ortho isomer is crowded and asymmetric → multiple signals. Para with different groups → two doublets (2H each).
Spectroscopy Hack Sheet
| Halogen pattern | Peaks | Ratio | Origin |
|---|---|---|---|
| 1 × Cl | M, M+2 | 3 : 1 | ³⁵Cl : ³⁷Cl ≈ 75% : 25% |
| 2 × Cl | M, M+2, M+4 | 9 : 6 : 1 | (3+1)² expansion |
| 1 × Br | M, M+2 | 1 : 1 | ⁷⁹Br : ⁸¹Br ≈ 50% : 50% |
| 2 × Br | M, M+2, M+4 | 1 : 2 : 1 | two-coin combinations |
| Benzene substitution | ¹H NMR |
|---|---|
| 1,4-disubstituted, identical groups (para) | 1 singlet, 4H |
| 1,4-disubstituted, different groups | 2 doublets, 2H each |
| 1,2-disubstituted (ortho) | multiple signals |
- Trap 1: the singlet must integrate to 4H — a 1H singlet is a different beast.
- Trap 2: low-resolution spectra can smear ortho's mess into a fake blob.
- Shortcut: read halogen counts from isotope ratios FIRST — it slaughters options before any arithmetic.