General Science
General Science tests school-level physics, chemistry and biology, usually through definitions, units, simple numericals and everyday applications.
Core rules
- Physics: SI units; Newton's three laws; work = force × displacement; power = work / time; speed is scalar, velocity is vector. Light reflects at equal angles; current follows Ohm's law, V = IR.
- Chemistry: atoms contain protons, neutrons and electrons; atomic number is protons. Acids have pH below 7, bases above 7, neutral is 7. Metals are generally sonorous, malleable and good conductors.
- Biology: the cell is the basic unit; mitochondria release energy; chloroplasts carry out photosynthesis. Blood carries oxygen via haemoglobin; vitamins A, B, C, D and K have specific deficiency diseases.
Worked example
A solution has hydrogen ion concentration 1 × 10^-4 mol/L. pH = -log10[H+] = -log10(10^-4) = 4. Since pH 4 is below 7, the solution is acidic. The reasoning depends on the logarithmic scale: each unit is a tenfold change in H+ concentration.
Traps
Mass is not weight; weight changes with gravity. A lower pH means stronger acidity, not weaker. Speed and velocity differ by direction. In photosynthesis, oxygen is released from water, not carbon dioxide. Check units before calculating.