General Science: Physics, Chemistry, Biology and Environment
General Science in the Group D paper tests school-level physics, chemistry, biology and environment, often with a Rajasthan ecology angle. Most marks come from units, definitions, human-body facts and everyday chemistry.
Physics
- SI units: metre (length), kilogram (mass), second (time), newton (force), pascal (pressure), watt (power).
- Newton's laws: inertia; F = ma; every action has an equal and opposite reaction.
- Work = force × displacement, measured in joules; speed of light ≈ 3 × 10⁸ m/s.
Chemistry
- Atomic number = number of protons; mass number = protons + neutrons. Isotopes share atomic number but differ in mass number.
- pH below 7 is acidic, 7 neutral, above 7 basic.
- Everyday formulae: baking soda NaHCO₃, washing soda Na₂CO₃·10H₂O, plaster of Paris CaSO₄·½H₂O, quicklime CaO.
Biology
- Mitochondria release energy as ATP; chloroplasts carry out photosynthesis; ribosomes synthesise protein.
- Human body: 206 bones in an adult, 12 pairs of cranial nerves, red blood cells live about 120 days.
Environment
- A food chain runs producer → primary consumer → decomposer, with roughly 10% energy transfer at each step.
- Stratospheric ozone absorbs ultraviolet radiation; major greenhouse gases are CO₂, CH₄, N₂O and CFCs.
- Rajasthan state symbols: Khejri (tree), Chinkara (animal), Godawan or Great Indian Bustard (bird), Rohida (flower).
Worked example
A force of 5 N moves a body 10 m along the direction of the force. Work = force × displacement = 5 × 10 = 50 J. Displacement here is along the force, so no cosine correction is needed.
Traps
Mass (kg) is not weight (newton); atomic number is not mass number; do not mix the state bird Godawan with the state animal Chinkara.