Study Notes: Basic Physics

Overview

Basic Physics forms a critical component of the General Science section in UPSSSC PET, typically contributing 4-6 questions from the total science allocation. This topic tests your understanding of fundamental physical principles that govern everyday phenomena—from why objects fall to how electricity flows through circuits.

Success in this section requires mastering conceptual clarity rather than complex calculations. UPSSSC PET emphasizes direct applications, unit identification, and understanding cause-effect relationships in physical systems. Students must be comfortable with basic numerical problems involving standard formulas and be able to identify correct physical principles in real-world scenarios. The questions test your grasp of motion, forces, energy transformations, heat transfer, light behavior, electrical circuits, and magnetic effects—all at a fundamental level suitable for undergraduate science curriculum.

Focus on understanding the "why" behind physical laws, memorizing standard units and constants, and practicing one-step numerical problems. This topic integrates well with your everyday observations, making it both scoring and conceptually satisfying when approached systematically.

Key Concepts

• **Motion** is change in position over time; velocity includes direction (vector) while speed does not (scalar). Acceleration is the rate of change of velocity.

• **Newton's Laws** govern force and motion: (1) objects resist change in motion (inertia), (2) force equals mass times acceleration (F = ma), (3) every action has an equal and opposite reaction.

• **Gravitation** is the universal attractive force between masses; weight is gravitational force on an object (W = mg), while mass remains constant everywhere.

• **Work** is done when force causes displacement in its direction; energy is the capacity to do work. Both are measured in joules. Energy transforms but total energy remains conserved.

• **Heat** is thermal energy transfer from hot to cold bodies; temperature measures hotness. Heat flows via conduction (direct contact), convection (fluid movement), and radiation (electromagnetic waves).

• **Light** travels in straight lines at 3 × 10⁸ m/s in vacuum; it reflects (bounces off) and refracts (bends when entering different media). Mirrors form images by reflection, lenses by refraction.

• **Electric current** is the flow of charge; voltage (potential difference) drives current through resistance. Power is the rate of energy consumption in electrical devices.

• **Magnetism** arises from moving charges; magnetic field lines emerge from north pole and enter south pole. Electric current produces magnetic fields (electromagnetic effect).