University Physics Study Notes

UNITS AND MEASUREMENT

  • Force: SI unit is Newton (N); 1\,N = 1\,kg \cdot ms^{-2}.

  • Work and Energy: SI unit is Joule (J). Commercial unit of energy is Kilowatt-hour (kWh); 1\,kWh = 3.6 \times 10^{6}\,J.

  • Power: SI unit is Watt (W). Industrial unit is Horsepower (746\,W = 1\,HP).

  • Pressure: SI unit is Pascal (Pa) or N/m^{2}.

  • Light-year: Unit of distance (9.461 \times 10^{12}\,km).

  • Resistivity: SI unit is Ohm-meter (\Omega m).

  • Luminous Intensity: SI unit is Candela (cd).

MECHANICS

  • Weight: A force (W = mg); SI unit is Newton.

  • Momentum: Vector quantity (p = mv); unit is kg \cdot ms^{-1}.

  • Acceleration (a): Rate of change of velocity (a = \frac{v-u}{t}).

  • Newton’s Laws:

    • 1st: Law of Inertia.

    • 2nd: F = ma.

    • 3rd: Action-Reaction (e.g., rocket launching).

  • Gravity: g = 9.8\,ms^{-2}. Value of g is maximum at poles, minimum at the equator, and zero at the Earth's center.

  • Centripetal Force: Acts toward the center in circular motion (F = \frac{mv^{2}}{r}).

PROPERTIES OF MATTER

  • Density: \rho = \frac{m}{V}. Water is densest at 4^{\circ}C (277\,K).

  • Archimedes’ Principle: Buoyant force equals the weight of fluid displaced.

  • Surface Tension: Tendency of liquid to minimize surface area (reason for spherical drops).

HEAT AND THERMODYNAMICS

  • Temperature Scales: K = ^{\circ}C + 273.15. Absolute zero is 0\,K (-273.15^{\circ}C).

  • Heat Transfer: Conduction (solids), Convection (fluids), Radiation (vacuum).

  • Thermodynamic Zeroth Law: Defines thermal equilibrium.

  • 1st Law: Conservation of energy.

SOUND AND WAVES

  • Sound Waves: Longitudinal mechanical waves; cannot travel in a vacuum.

  • Audible Range: 20\,Hz to 20,000\,Hz.

  • Wave Equation: v = f\lambda.

  • Echo: Requires a minimum distance of 17.2\,m; sound persists for 0.1\,s.

  • SONAR: Uses ultrasound for underwater distance/speed measurement.

OPTICS

  • Snell’s Law/Refraction: Bending of light between mediums. Speed of light (c \approx 3 \times 10^{8}\,ms^{-1}).

  • Mirrors:

    • Concave: Converging; used in headlights and by dentists.

    • Convex: Diverging; used for vehicle rear-view mirrors.

  • Human Eye Defects:

    • Myopia: Near-sightedness; corrected by concave lens.

    • Hypermetropia: Far-sightedness; corrected by convex lens.

  • Dispersion: Splitting white light into VIBGYOR colors using a prism.

ELECTRICITY AND MAGNETISM

  • Ohm’s Law: V = IR.

  • Resistors:

    • Series: R{s} = R{1} + R_{2}.

    • Parallel: \frac{1}{R{p}} = \frac{1}{R{1}} + \frac{1}{R_{2}}.

  • Electric Power: P = VI = I^{2}R = \frac{V^{2}}{R}.

  • Electromagnetic Induction: Generation of current via relative motion (Michael Faraday).

  • Transformer: Changes voltage levels based on mutual induction.

NUCLEAR PHYSICS AND INVENTIONS

  • Fission: Heavy nucleus splits (Nuclear reactors).

  • Fusion: Light nuclei combine (energy source of the Sun).

  • India's First Reactor: Apsara (1956).

  • Key Inventors: Einstein (Relativity, E=mc^{2}), Röntgen (X-rays), Graham Bell (Telephone), Edison (Bulb).