General Science — Study Notes for SSC CHSL
Overview
General Science contributes approximately 15–20 questions out of 100 in SSC CHSL Tier 1, making it a crucial scoring area. This section tests basic concepts from high school Physics, Chemistry and Biology—not advanced theory. Questions are typically factual ("What is the SI unit of force?") or application-based ("Which vitamin deficiency causes scurvy?").
Success requires memorizing fundamental definitions, units, processes and organ functions rather than deriving complex equations. The exam focuses on everyday science: how things work, what causes what, and standard classifications. Most questions can be answered in 10–15 seconds if you have the factual base locked in. Candidates who neglect this section lose easy marks, while those who systematically cover all three branches gain a decisive edge.
Your strategy: build a strong foundation in Physics laws and units, Chemistry's periodic trends and reactions, and Biology's human body systems. Prioritize high-frequency topics like vitamins, diseases, simple machines, acids-bases, and cell structure. Revise using flashcards for quick recall on exam day.
Key Concepts
- **Physics is measurement and motion**: Force, energy, work, power and their SI units form the backbone. Newton's laws govern motion; simple machines multiply force or speed.
- **Electricity basics matter**: Current (ampere), voltage (volt), resistance (ohm) and Ohm's law (V = IR) appear frequently. Know series vs parallel circuits and how household electricity works.
- **Light and optics**: Reflection, refraction, mirrors (concave/convex), lenses and the human eye. Remember: convex lens converges light, concave diverges.
- **Chemistry revolves around elements and reactions**: The periodic table organizes elements by atomic number. Metals, non-metals and metalloids have distinct properties.
- **Acids, bases and salts are exam favorites**: pH scale (0–14), common acids (HCl, H₂SO₄), bases (NaOH, Ca(OH)₂) and neutralization reactions yield salt + water.
- **Biology emphasizes the human body**: Know the function of major organs (heart pumps blood, lungs exchange gases, kidneys filter waste) and systems (circulatory, respiratory, digestive, nervous).
- **Vitamins and diseases link directly**: Vitamin A (vision), B-complex (energy), C (scurvy), D (rickets), E (antioxidant), K (clotting). Deficiency diseases appear in 2–3 questions every year.
- **Cell is the basic unit of life**: Prokaryotic (no nucleus, bacteria) vs eukaryotic (nucleus present, animals/plants). Organelles: mitochondria (powerhouse), ribosomes (protein synthesis), chloroplasts (photosynthesis in plants).
Formulas / Key Facts
**Physics**
- Speed = Distance / Time; SI unit: m/s
- Force = Mass × Acceleration; SI unit: newton (N)