PHYSICS Test Preparation | Most Important Concepts for Army, Navy & PAF

Welcome to your all-in-one physics reference guide! 📚 Whether you’re preparing for the PAF, Pak Army, Navy, Cadet Colleges, or board exams, this detailed post will help you review the most important units, formulas, definitions, and scientific values from physics in a clear and easy-to-read format. Let’s dive in! ⬇️

⚖️ Physics Units List

Here are the standard units used in physics you must memorize:

📐 Physics Formulas & Equations

Below is a comprehensive list of essential equations for physics exam prep:

📏 Standard Scientific Values

Memorizing values is key for objective-type tests:

💡 Basic Physics Definitions and Concepts (Easy to Learn)

⚙️ Work, Power, Energy & Motion

• Work: Product of force and displacement in the direction of force.

• Power: Rate of doing work.

• Energy: Capacity to do work.

• Kinetic Energy: Energy due to motion.

• Potential Energy: Energy due to position.

• Gravitational Potential Energy: Energy due to height from Earth’s surface.

• Efficiency: Ratio of output to input.

• Mechanical Advantage: Ratio of load to effort.

🧲 Force, Mass & Motion

• Force: Push or pull.

• Torque: Rotational effect of force.

• Inertia: Tendency of a body to resist change in motion.

• Mass: Quantity of matter in a body.

• Velocity: Rate of change of displacement.

• Speed: Distance covered per unit time.

• Acceleration: Rate of change of velocity.

• Momentum: Product of mass and velocity.

🧪 Pressure, Stress & Strain

• Pressure: Force per unit area (perpendicular).

• Stress: Force exerted on unit area.

• Strain: Change in shape due to stress.

• Tensile Stress: Ratio of change in length to original length.

• Young’s Modulus: Ratio between stress and strain.

• Hooke’s Law: Relationship between stress and strain.

🔌 Current Electricity

• Current: Flow of electrons.

• Conductor: Allows current to pass easily.

• Insulator: Does not allow current to pass easily.

• Resistance: Opposition to flow of current.

• Ammeter: Measures current, connected in series.

• Voltmeter: Measures voltage, connected in parallel.

• Galvanometer: Detects current.

• Capacitor: Stores electric charge.

🔋 Semiconductors & Electronics

• N-type Material: Electron is the charge carrier.

• P-type Material: Hole is the charge carrier.

• Diode:

  • P-side = Anode

  • N-side = Cathode

• Transistor Types:

  1. NPN Transistor

  2. PNP Transistor

• Transistor: Works as amplifier.

• Types of Current:

  • Alternating Current (AC)

  • Direct Current (DC)

🔍 Measurement Tools

• Micrometer: Measures up to 0.01 mm.

• Barometer: Measures air pressure.

🌍 Physics Branches

• Geophysics: Study of Earth’s internal structure.

• Solid State Physics: Properties of matter in solid form.

• Nuclear Physics: Study of atomic nuclei.

• Molecular Physics: Study of atoms and molecules.

• Electromagnetism: Study of electric and magnetic fields.

• Biophysics: Physics applied to biology.

🔄 Laws of Physics

• Newton’s First Law: Law of inertia.

• Charles’s Law: Pressure remains constant.

• Boyle’s Law: Temperature remains constant.

• Pascal’s Law: Used in hydraulic brakes.

⚙️ Simple Machines

• Lever: A bar that rotates around a point.

• Fulcrum: The point around which lever rotates.

• Inclined Plane: A sloped surface.

💧 Fluids & Motion

• Viscosity: Friction between layers of a fluid.

• Evaporation: Liquid turns into vapor without boiling.

• Brownian Motion: Random motion of particles.

🌐 Wave & Light

• Transverse Wave: Has crests and troughs.

• Reflection: Angle of incidence = angle of reflection.

• Total Internal Reflection: Occurs when angle > critical angle.

• Critical Angle: Angle where refracted ray travels along boundary.

• Refraction: Light bends when passing from one medium to another.

  • From denser to rarer: light bends away from normal.

🔍 Optics

• Convex Mirror: Outer surface reflects.

• Concave Mirror: Inner surface reflects.

• Convex Lens: Thicker in center.

• Concave Lens: Thinner in center.

• Types of Mirrors:

  1. Concave

  2. Convex

• Types of Lenses:

  1. Concave

  2. Convex

📐 Motion Types

• Types of Motion:

  1. Translatory

  2. Vibratory

  3. Rotatory

• Types of Translatory Motion:

  1. Linear

  2. Random

  3. Circular

• S.H.M (Simple Harmonic Motion): Motion of pendulum or spring.

⚛️ Atomic & Nuclear

• Atomic Number: Number of protons in the nucleus.

• Mass Number: Protons + Neutrons.

• Beta Rays: Negative charge.

• Alpha Rays: Positive charge.

• Gamma Rays: No charge.

• Bimetallic Strip: Used in thermostats and fire alarms.

📘 Other Key Concepts

• Energy = Charge × Potential Difference

• Work = Force × Displacement

• Resistance increases when temperature increases.

• Centripetal Force: Force directed toward the center in circular motion.

• Rolling Friction is 100x less than sliding friction.

• Pitch depends on frequency.

• Kinetic Energy, Momentum, and Density depend on mass.

• Unit of Inertia depends on mass and displacement.

📚 Key Physics Definitions

⚙️ Types of Motion

⚗️ Density of Common Substances (kg/m³)

💡 Tip: Make sure to revise these daily to retain maximum memory for tests. Most MCQs and short questions in forces tests and boards are taken from these core concepts.

📥 Want more learning resources or quizzes? Visit our Practice Test Page or explore physics test series and books by Sohail Ibrar (Ex-PAF) on this site!