General Science
General Science covers physics, chemistry and biology at Class 10 level, applied to everyday and laboratory contexts. Expect units and measurement, motion and force, light, electricity, acids–bases–salts, atomic structure, human physiology, nutrition and common diseases.
Core concepts
- SI base units: metre, kilogram, second, ampere, kelvin, mole, candela. Force is in newtons, pressure in pascals, energy in joules.
- Newton's laws: F = ma; every action has an equal and opposite reaction; inertia resists change of motion.
- Ohm's law V = IR; power P = VI; resistances add in series, while reciprocals add in parallel.
- pH runs 0–14; each unit is a tenfold change in hydrogen-ion concentration; acid + base gives salt + water.
- Blood: plasma, RBCs (haemoglobin, oxygen transport), WBCs (immunity), platelets (clotting); O negative is the universal donor, AB positive the universal recipient.
- Vitamins: A for vision, B-complex deficiency causes beriberi, C deficiency causes scurvy, D deficiency causes rickets.
Worked example
A 10 kg block accelerates at 2 m/s². The force needed is ma = 10 × 2 = 20 N. Its weight, however, is mg = 10 × 9.8 = 98 N, because weight is the gravitational force on that mass. The reasoning matters: the same mass produces two different numbers depending on whether the question asks for applied force or weight.
Traps
- Reporting mass where weight in newtons is asked, or the reverse.
- Treating pH 3 as twice as acidic as pH 5; it is one hundred times.
- Swapping arteries, which carry blood away from the heart, with veins, which carry it back.
- Confusing atomic number (protons) with mass number (protons plus neutrons).