General Science
Syllabus band
Questions sit at Class 8-10 level: definitions, SI units, simple one-step numericals and everyday applications. Nothing needs calculus; accuracy on units and terminology decides the score.
Physics
- Newton's laws: inertia explains why a standing passenger in a bus falls backward when the bus starts suddenly.
- Ohm's law, V = IR; power P = VI; domestic energy is billed in kWh, which is a unit of energy, not power.
- Light: reflection and refraction, mirror and lens formulae; myopia corrected by a concave lens, hypermetropia by a convex lens.
- Motion: v = u + at, and average speed = total distance ÷ total time.
Chemistry
- Atomic number equals the number of protons; valency decides formulae.
- pH below 7 is acidic, above 7 basic; litmus and phenolphthalein are common indicators, and acid plus base gives salt and water.
- Common salts: baking soda NaHCO₃, washing soda Na₂CO₃·10H₂O, quicklime CaO, plaster of Paris.
Biology
- Cell: mitochondria release energy, chloroplasts carry out photosynthesis, the nucleus holds genetic material.
- Blood: red cells carry haemoglobin, white cells give immunity, platelets help clotting.
- Deficiencies: vitamin A - night blindness; B1 - beri-beri; C - scurvy; D - rickets; iodine - goitre.
- Vectors: Anopheles mosquito spreads malaria, Aedes spreads dengue.
Worked example
A force of 20 N moves a box 5 m in the direction of the force. Work = force × displacement = 20 × 5 = 100 joule. If the force were perpendicular to motion, work would be zero.
Traps
- Mass is in kilograms, weight in newtons; a body's mass does not change on the Moon.
- Sound cannot travel through a vacuum.
- Do not swap the units of potential difference (volt) and current (ampere).