24 hours to exam? This page tells you exactly what to focus on, what to skip, and how to manage your time tomorrow.
CBSE Class 10 Science
24 Hours Before the Exam
No time for everything. This guide tells you exactly what to revise, which topics almost certainly appear, what mistakes to avoid, and how to manage your 3 hours in the exam hall.
Focus on These Chapters First
- Electricity — Ohm's law, series/parallel resistance formulas + numericals
- Light — mirror and lens formula, power of lens, ray diagrams
- Chemical Reactions — types (combination, decomposition, displacement, redox)
- Life Processes — nutrition, respiration, transport, excretion diagrams
- Heredity — Mendel's laws, monohybrid and dihybrid cross
- Carbon Compounds — functional groups, IUPAC naming, esterification
- Acids, Bases & Salts — pH scale, neutralisation, important reactions
- Human Reproduction — male and female reproductive system diagrams
Key Formulas & Facts to Memorise Right Now
- V = IR | P = VI = I²R = V²/R | Resistors in series: R = R₁+R₂ | Parallel: 1/R = 1/R₁+1/R₂
- Mirror formula: 1/f = 1/v + 1/u | Magnification m = -v/u
- Lens formula: 1/f = 1/v - 1/u | Power P = 1/f(in metres)
- Photosynthesis: 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
- Respiration (aerobic): C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 38 ATP
- pH < 7: acid | pH = 7: neutral | pH > 7: base
- Rusting: 4Fe + 3O₂ + xH₂O → 2Fe₂O₃.xH₂O (iron oxide hydrate)
- Reaction of Na with water: 2Na + 2H₂O → 2NaOH + H₂ (exothermic)
Timing Strategy for 3 hours Exam
- 1First 15 min: Read the full paper, mark questions you're confident about
- 20–30 min: All 1-mark questions (MCQs + very short answer)
- 330–80 min: 2-mark and 3-mark questions — write to the point, don't over-explain
- 480–150 min: 5-mark questions — include diagrams, use headings for multi-part answers
- 5150–170 min: Case study questions — relate to chapters you know
- 6Last 10 min: Check all diagram labels and units in numericals
Common Mistakes — Avoid These Tomorrow
- ✕Not labelling diagrams — every label in a diagram carries marks
- ✕Confusing concave and convex in mirror/lens questions
- ✕Using wrong sign convention in mirror formula (real is negative)
- ✕Forgetting to balance chemical equations before writing the type of reaction
- ✕Writing vague answers for 3-mark questions — be specific and list 3 distinct points
- ✕Skipping units in electricity numericals (volts, amperes, ohms, watts)
Must Attempt — Never Leave These Blank
- ✓All electricity numericals — formula-based, guaranteed marks
- ✓All diagram-based questions — even a rough correct diagram gives full diagram marks
- ✓Chemical equation balancing — always attempt and verify atom count
- ✓Life processes — definition + function format always scores full marks
Skip If Unsure (Return If Time Permits)
- →Complex genetics problems if you can't recall the cross — move on and return
- →Detailed mechanism questions in Carbon Compounds if unsure of steps
Remember: Partial marks exist. Attempt and leave if stuck — come back if time allows. Never spend more than 8 minutes on a single 5-mark question.
Science has a perfect balance — Biology is mostly memory, Physics is mostly formulas, Chemistry is mostly reactions. You don't need to master everything. Focus on what you know and present it clearly.
Night Before — Non-Academic Checklist
Pack your bag
Admit card, 2 pens, pencil, eraser, ruler, geometry box (if needed)
Sleep by 10 PM
Your brain consolidates memory during sleep. Late-night cramming hurts more than it helps
Stop studying at 9 PM
Whatever you don't know by tonight won't be learnt in an hour. Trust your preparation
Set two alarms
One to wake up, one as a backup. Arrive at the centre 30 minutes before the exam
More resources for Class 10 Science
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