Study Notes: Physics (SSC CGL General Awareness)

Overview

Physics questions in SSC CGL Tier 1 typically account for 3–5 marks within the General Science section. The exam tests basic conceptual understanding rather than numerical problem-solving. Questions are fact-based and focus on everyday applications of physical principles—how devices work, units of measurement, laws and their discoverers, and fundamental phenomena.

The syllabus covers four broad areas: **Mechanics** (motion, force, energy), **Electricity** (current, circuits, devices), **Optics** (light, mirrors, lenses), and **Modern Physics** (atomic structure, radioactivity, recent discoveries). Success requires memorizing key definitions, units, laws, and real-world applications. Students should focus on static facts—SI units, scientist-discovery pairs, and how common instruments operate—rather than derivations or complex calculations.

This topic integrates well with Chemistry and Biology in the General Science section, and understanding basic physics improves performance on technology-related Current Affairs questions.

Key Concepts

• **Force and Motion**: Newton's three laws govern all motion. First law (inertia), second law (F = ma), third law (action-reaction). Understand friction as a force opposing motion and gravity as the force attracting objects toward Earth.

• **Energy Forms**: Energy cannot be created or destroyed, only converted (Law of Conservation of Energy). Kinetic energy is energy of motion; potential energy is stored energy. Work is force applied over distance.

• **Current Electricity**: Electric current is flow of electrons. Conductors allow flow (copper, silver); insulators resist it (rubber, plastic). Ohm's Law (V = IR) relates voltage, current, and resistance.

• **Light Behavior**: Light travels in straight lines, reflects off surfaces, and refracts (bends) when entering different media. Mirrors form images by reflection; lenses by refraction. Dispersion splits white light into colors.

• **Atomic Structure**: Atoms consist of protons (positive), neutrons (neutral), and electrons (negative). Radioactivity is spontaneous emission of particles/energy from unstable nuclei.

• **Waves and Sound**: Sound requires a medium and travels as longitudinal waves. Light is an electromagnetic wave that can travel through vacuum. Frequency determines pitch; amplitude determines loudness.

Formulas / Key Facts

• **SI Units**: Length (meter), Mass (kilogram), Time (second), Current (ampere), Temperature (kelvin), Force (newton), Energy (joule), Power (watt), Pressure (pascal)