Comprehensive Physics Study Notes: Form One to Form One through Form Four

Introduction to Science and Physics

• Science in Our Lives

  • Scientists are individuals trained in science who practice scientific knowledge.
  • Industries require professionals such as engineers, technicians, and researchers.
  • Hospitals require doctors, nurses, and technologists.
  • Science provides powerful ideas, instruments, and methods that influence daily life.

• Scientific Vocabulary and Methods

  • Laboratory: A building specifically designed for scientific work, containing various apparatus and materials.
  • Hypothesis: A scientific fact or statement that has not yet been proven or experimented upon.
  • Law / Principle: A scientific fact or statement proven and experimented to be true under all conditions.
  • Theorem: A fact or statement that is true and proven but applicable only under specific conditions.

• Defining Physics

  • The word "Physics" originates from the Greek word for "nature."
  • It deals with natural phenomena.
  • Objective: The study of the components of matter and their mutual interactions.
  • Secondary Definition: The study of matter and its relation to energy.
  • A physicist explains the bulk properties of matter and observed phenomena.

• Branches of Physics

  1. Mechanics: The study of the motion of bodies under the influence of force.
  2. Electricity: Deals with the movement of charge from one point to another through a conductor.
  3. Magnetism: The study of magnets and magnetic fields and their applications.
  4. Thermodynamics / Heat: The study of the transformation of heat from one form to another.
  5. Optics: The study of light as it travels between different media.
  6. Waves: The study of disturbances traveling through mediums or a vacuum.
  7. Particle Physics
  8. Nuclear Physics
  9. Plasma Physics

• Relation to Other Subjects and Careers

  • Physics forms the base of natural science.
  • Biology and Chemistry use physics to explain processes in living organisms.
  • Applied sciences like meteorology and astronomy utilize physical techniques.
  • Career opportunities include: Engineering (Civil, Electrical, Mechanical, Agricultural, Environmental, Chemical, Computer), Meteorology, Surveying, Geology, and Astronomy.
  • Note: All science-based careers (doctors, pharmacists, etc.) require physics as a foundation.

• Laboratory Safety Rules

  1. Observe proper dressing: no loose clothing, tied hair, and closed shoes.
  2. Identify locations of electricity switches, fire-fighting equipment, first aid kits, gas, and water systems.
  3. Keep windows open.
  4. Follow instructions; never attempt anything in doubt.
  5. No eating or drinking.
  6. Turn off electrical, gas, and water taps when not in use.
  7. Keep surfaces dry; wipe spillages immediately.
  8. Clean and return apparatus to correct storage.
  9. Wash hands before leaving.
  10. Report accidents to the teacher immediately.

Measurement I

• International System of Units (SI)

  • Established in 1971.
  • Basic Quantities and SI Units:
    1. Length: Metre ($m$)
    2. Mass: Kilogram ($kg$)
    3. Time: Second ($s$)
    4. Electric Current: Ampere ($A$)
    5. Thermodynamic Temperature: Kelvin ($K$)
    6. Luminous Intensity: Candela ($cd$)
    7. Amount of Substance: Mole ($mol$)
  • Derived Quantities: Obtained from basic quantities (e.g., Area, Volume).

• Length

  • Definition: The measure of distance between two points in space.
  • Conversion Factors:
    • $1\,km = 1000\,m$
    • $1\,Hm = 100\,m$
    • $1\,Dm = 10\,m$
    • $1\,mm = 0.001\,m$
  • Instruments: Metre rule ($100\,cm$), tape measure ($100\,m$, $300\,m$, $500\,m$).

• Area

  • Definition: Measure of the extent of a surface ($m^2$).
  • Formula-based for regular bodies; approximations for irregular bodies.

• Volume

  • Definition: Amount of space occupied by matter ($m^3$).
  • Sub-multiples: $cm^3$, $mm^3$, and litre ($l$).
  • Conversions: $1\,m^3 = 1,000,000\,cm^3$; $1\,l = 1,000\,cm^3$.
  • Instruments: Measuring cylinder, eureka can, pipette, burette, volumetric flask, beaker.

• Mass

  • Definition: Quantity of matter in a substance.
  • Matter: Anything that occupies space and has weight.
  • Units: Kilogram ($kg$), gram ($g$), milligram ($mg$), tonne ($t$).
  • Conversions: $1\,kg = 1,000\,g = 1,000,000\,mg = 0.001\,tonnes$ (Note: Transcript says $1,000,000\,mg = 100\,tonnes$; however, $1\,t = 1000\,kg$).
  • Instrument: Beam balance.

• Density ($\rho$)

  • Definition: Mass per unit volume.
  • Formula: $\text{Density} = \frac{\text{mass}}{\text{volume}}$.
  • SI Units: $kg/m^3$ or $kgm^{-3}$.
  • Example 1: Mass of glass block = $187.5\,g$, Dimensions = $5.0\,cm \times 2.0\,cm \times 7.5\,cm$.
    • $\text{Volume} = 5.0 \times 2.0 \times 7.5 = 75.0\,cm^3$.
    • $\text{Density} = \frac{187.5}{1000} / \frac{75}{1000000} = 2,500\,kgm^{-3}$.
  • Example 2: Density of acid = $1.8\,g/cm^3$, Mass = $3.1\,kg$.
    • $\text{Volume} = \frac{3100}{1.8} = 1,722\,cm^3$.

• Common Densities ($kg/m^3$)

  • Platinum: $21,400$
  • Gold: $19,300$
  • Mercury: $13,600$
  • Lead: $11,300$
  • Water: $1,000$
  • Ice: $920$
  • Air: $1.31$
  • Hydrogen: $0.089$

• Relative Density ($d$)

  • Definition: Density of a substance compared to water.
  • Equation: $d = \frac{\text{Density of substance}}{\text{Density of water}}$.
  • It has no units as it is a ratio.
  • Instrument: Relative density bottle.

• Time

  • Measure of duration. SI unit: Second ($s$).
  • Sub-multiples: millisecond, microsecond, minute, hour, day, week, year.
  • Instruments: Clocks, stopwatches, digital watches.

• Accuracy and Errors

  • Accuracy: Closeness of a measurement to the correct value.
  • Error: Deviation of measurement from the correct value.
  • $\% \text{ error} = (\frac{\text{sensitivity}}{\text{size measured}}) \times 100$.

Forces

• Definition: A push or a pull that changes a body’s state of motion or shape.

• SI Unit: Newton ($N$). It is a vector quantity.

• Types of Forces:

  1. Gravitational Force: Attraction between two masses. Earth's pull is called weight.
  2. Friction: Opposes relative motion between surfaces. Friction in fluids is viscosity.
  3. Tension: Pull or compression in a string or spring.
  4. Upthrust: Upward force on an object in a fluid.
  5. Cohesive vs Adhesive: Cohesive is attraction between same molecules; adhesive is between different types.
  6. Magnetic Force: Attraction or repulsion in magnets.
  7. Electrostatic Force: Attraction or repulsion between static charges.
  8. Centripetal Force: Constrains a body to move in a circular path.
  9. Surface Tension: Causes liquid surfaces to behave like a stretched skin. Reduced by impurities (detergent) and temperature rise.

• Mass vs Weight

  • Mass: Quantity of matter ($kg$), constant everywhere, scalar (magnitude only), measured with beam balance.
  • Weight: Pull of gravity ($N$), changes with location, vector (magnitude and direction), measured with spring balance.
  • Formula: $W = mg$.
  • Example: Astronaut weighs $900\,N$ on Earth ($g = 10\,N/kg$) and $150\,N$ on Moon.
    • $\text{Mass} = \frac{900}{10} = 90\,kg$.
    • $\text{Moon's } g = \frac{150}{90} = 1.67\,N/kg$.

Pressure

• Definition: Normal (perpendicular) force per unit area.

• SI Unit: Newton per metre squared ($N/m^2$) or Pascal ($Pa$).

• Formula: $\text{Pressure} = \frac{\text{Force}}{\text{Area}}$.

• Units: $1\,bar = 10^{5}\,N/m^2$; $1\,millibar = 100\,N/m^2$.

• Maximum/Minimum Pressure: A brick exerts maximum pressure on its smallest face and minimum pressure on its largest face.

• Pressure in Liquids

  • Formula: $P = h \rho g$.
  • Pressure depends on depth ($h$) and density ($\rho$).
  • Example: Diver at $10\,m$ depth in water ($\rho = 1000\,kgm^{-3}$).
    • $P = 10 \times 1000 \times 10 = 100,000\,Nm^{-2}$.

• U-Tube Manometer

  • Used to measure gas pressure. $P_1 = P_0 + h \rho g$.
  • If a man blows into a U-tube causing a $40\,cm$ water difference: Lung pressure = $(1.01 \times 10^{5}) + (0.4 \times 10 \times 1000) = 1.05 \times 10^{5}\,N/m^2$.

• Barometers

  • Simple Mercury Barometer: Glass tube ($1\,m$) inverted in mercury. Sea level height is $760\,mm$.
  • Torricellian Vacuum: The space above the mercury column.
  • Standard Atmospheric Pressure: $1.014 \times 10^{5}\,Pa$ (approx. $1\,bar$).
  • Fortin Barometer: More accurate; uses an adjusting screw.
  • Aneroid Barometer: Uses a contracting metal box; can be calibrated for altitude (altimeter).
  • Bourdon Gauge: Used in gas cylinders; measures both gas and liquid pressure.

• Applications

  • Rubber Sucker: Atmospheric pressure holds it against surfaces.
  • Drinking Straw / Syringe: Sucking creates low pressure, atmospheric pressure pushes liquid in.
  • Bicycle Pump: Uses leather valve and tire valve to lock air inside.
  • Siphon: Hollow tube used to empty tanks via pressure difference ($h \rho g$).
  • Hydraulic Systems (Pascal's Principle): Pressure applied to an incompressible fluid is transmitted equally in all directions.
    • Brake System: Master cylinder transmits pressure to slave cylinders to move brake shoes.
    • Hydraulic Press: $\frac{F_1}{A_1} = \frac{F_2}{A_2}$. Used to lift heavy loads.

Particulate Nature of Matter

• States of Matter: Solid, Liquid, Gas.
• Physical Changes: Reversible, no new substances (e.g., melting, dissolving, magnetizing).
• Chemical Changes: Irreversible, new substances formed (e.g., burning, reactions).
• Nuclear Changes: Nuclei give off particles (Uranium, Radium) and change into new substances.
• Kinetic Theory:
  • Atoms: Tiny particles composing matter; contain protons, neutrons, and electrons.
  • Diffusion: Movement from high to low concentration. Gases diffuse faster than liquids.
  • Solids: Strong attraction, small spaces, fixed vibration, fixed shape.
  • Liquids: Weaker attraction, restricted but free motion, takes container shape.
  • Gases: Negligible attraction, independent motion, no definite shape/volume.

Thermal Expansion

• Temperature: Degree of hotness or coldness. Units: Celsius ($^{\circ}C$) and Kelvin ($K$). Absolute zero is $0\,K$.

• Expansion in Solids:

  • Ball and Ring Experiment: Heated ball expands and cannot pass through the ring; slips through upon cooling.
  • Bar-breaker: A cooling contracting bar exert enough force to break a cast-iron pin.
  • Bimetallic Strip: Consists of different metals (e.g., Brass and Iron). Brass expands more than Iron, causing the strip to bend toward the Iron side.
  • Applications: Railway expansion joints, rollers on bridges, rivets for metal plates, thermostats in irons/alarms.

• Expansion in Liquids/Gases:

  • Liquids expand more than solids.
  • Gases expand the most; demonstrated by bubbles escaping a flask when warmed by hands.
  • Land and Sea Breezes: Caused by convection currents due to air expansion.

• Thermometers:

  • Liquid-in-glass: Uses mercury ($-39^{\circ}C$ to $357^{\circ}C$) or alcohol ($-112^{\circ}C$ to $78^{\circ}C$).
  • Clinical: Narrow bore for accuracy; constriction prevents mercury from retreating.
  • Six's Maximum/Minimum: Records temp ranges using oil of creosote and mercury.
  • Bimetallic: Strip unwinds with heat to move a pointer.
  • Thermocouple: Uses copper-iron junctions; potential difference relates to temperature.

• Unusual Expansion of Water: Water contracts when heated from $0^{\circ}C$ to $4^{\circ}C$. It is most dense at $4^{\circ}C$. This allows ice to float and supports marine life in winter.

Heat Transfer

• Conduction: Heat transfer in solids.
  • Factors: Temperature difference, cross-sectional area, length, and material type.
  • Experiment: Rods of Copper, Aluminium, Brass, and Iron. Copper conducts fastest.
• Convection: Heat transfer in fluids via density changes.
  • Demonstrated via smoke boxes (air) or potassium permanganate crystals (water).
  • Applications: Land/sea breezes, car radiators, immersion heaters.
• Radiation: Heat transfer via electromagnetic waves.
  • Leslie Cube: Dull black surfaces are the best emitters/absorbers; polished silver are the worst.
  • Applications: Chrome/silver coats on kettles/irons, greenhouses, vacuum flask features.
• Vacuum Flask (Dewar Flask):
  1. Vacuum prevents conduction and convection.
  2. Silvered walls minimize radiation.
  3. Cork supports/stopper prevent conduction.

Rectilinear Propagation and Reflection

• Light Behavior:
  • Luminous: Produce own light (Sun).
  • Opaque: No light passes.
  • Translucent: Light passes, but blurry (frosted glass).
  • Transparent: Clear passage (window pane).
• Pinhole Camera: Forms an inverted image. $\text{Magnification} = \frac{\text{image height}}{\text{object height}} = \frac{\text{image distance}}{\text{object distance}}$.
• Shadows: Umbra (dark center) and Penumbra (lighter outer patch).
• Eclipses:
  • Solar: Moon between Sun and Earth.
  • Lunar: Earth between Sun and Moon.
• Reflection:
  1. Regular: Parallel beam on smooth surface.
  2. Diffuse: Rough surface scatters light.
  3. Laws: Angle of incidence ($i$) = Angle of reflection ($r$); incident ray, normal, and reflected ray lie in one plane.
  4. Plane Mirror Images: Same size, same distance, laterally inverted, virtual, erect.
  5. Angular Mirrors: Number of images $n = (\frac{360^{\circ}}{\theta}) - 1$.

Electrostatics I

• Charges: Positive (protons) and Negative (electrons). Like charges repel; unlike attract.
• Unit: Coulomb ($C$). Charge on one electron = $1.60 \times 10^{-19}\,C$.
• Leaf Electroscope: Detects and measures charge. A charged body causes the leaf to diverge.
• Induction: Charging without contact.
• Applications: Electrostatic precipitators (pollution control), spray painting, photocopying.
• Hazards: Sparks from fuel flowing in pipes. Use metallic cans to leak out charge.

Cells and Simple Circuits

• Current ($I$): Rate of flow of charge. $I = \frac{Q}{t}$. SI unit: Ampere ($A$).
• Potential Difference ($V$): Work done per unit charge moving between points.
• Primary Cells: Cannot be recharged (e.g., Simple cell, Leclanch
  e, Dry cell).
  • Defects: Polarization (hydrogen bubbles on anode) and Local Action (acid reacting with zinc impurities).
• Secondary Cells: Rechargable storage cells (e.g., Lead-acid accumulator, Alkaline cells).
  • Lead-acid: Rated in ampere-hours ($Ah$). A $30\,Ah$ battery provides $3\,A$ for $10\,hours$.
  • Alkaline: NiCd or NiFe. Portable and low maintenance but expensive.

Magnetism

• Materials:
  • Ferromagnetic: Strongly attracted (Iron, Steel, Cobalt, Nickel).
  • Paramagnetic: Weakly attracted.
  • Diamagnetic: Repelled.
• Domain Theory: Unmagnetized materials have domains in random directions; magnetization aligns them until saturated.
• Properties: North and South poles; repulsion is the only sure test.
• Making Magnets: Induction, stroking, or electric current through a solenoid.
• Demagnetizing: Hammering (E-W), heating, or using A.C. in a solenoid.

Measurement II

• Vernier Callipers: Accuracy of $0.10\,mm$. Uses a main scale ($cm/mm$) and a vernier scale ($10$ divisions of $0.9\,mm$).
• Micrometer Screw Gauge: Accuracy of $0.01\,mm$. Uses a sleeve scale ($0.5\,mm$ divisions) and a thimble scale ($50$ divisions of $0.01\,mm$).
• Oil Drop Experiment: Estimating molecular size. $\text{Thickness } h = \frac{\text{Volume } V}{\text{Area } A}$.

Turning Effect of Force

• Moment: Force ($N$) $\times$ Perpendicular distance from pivot ($m$).
• Law of Moments: For equilibrium, $\sum \text{Clockwise Moments} = \sum \text{Anti-clockwise Moments}$.
• Lever: Effort, Load, and Fulcrum. Uses moments to simplify work.

Equilibrium and Stability

• Centre of Gravity (C.G): Point where total weight appears to act.
• Stability Factors: Base area (wider is better) and C.G height (lower is better).
• States of Equilibrium:
  1. Stable: Returns after small displacement.
  2. Unstable: Topples over after small displacement.
  3. Neutral: Stays at rest in any position.

Linear Motion

• Kinematics: Disregarding forces. Dynamics: Considering forces.
• Scalars: Distance, Speed. Vectors: Displacement, Velocity, Acceleration.
• Equations of Motion:
  1. $v = u + at$
  2. $s = ut + \frac{1}{2}at^2$
  3. $v^2 = u^2 + 2as$ (where $u$ = initial velocity, $v$ = final velocity, $a$ = acceleration, $s$ = displacement, $t$ = time).
• Motion Under Gravity: Use $g = 10\,m/s^2$. Time of flight $T = \frac{2u}{g}$. Max height $H = \frac{u^2}{2g}$.
• Graphs: Gradient of Displacement-Time = Velocity; Gradient of Velocity-Time = Acceleration; Area under Velocity-Time = Displacement.

Refraction of Light

• Definition: Change of direction of light when passing between different optical densities.
• Snell’s Law: $\frac{\sin(i)}{\sin(r)} = n$ (Refractive Index).
• Refractive Index (Velocity): $n = \frac{\text{velocity in vacuum}}{\text{velocity in material}}$.
• Depth: $n = \frac{\text{real depth}}{\text{apparent depth}}$.
• Total Internal Reflection (TIR): Occurs when light travels from denser to less dense medium and angle of incidence exceeds critical angle ($C$). $\sin(C) = \frac{1}{n}$.
• Applications: Mirages, periscopes, binoculars, optical fibers, dispersion (rainbows).

Newton’s Laws of Motion

1. First Law (Inertia): A body stays at rest or uniform motion unless acted upon by a force.
2. Second Law (Momentum): Rate of change of momentum is proportional to applied force. $F = ma$. Change in momentum = Impulse ($F \Delta t = mv - mu$).
3. Third Law (Interaction): Action and reaction are equal and opposite.

• Collisions:
  • Elastic: Momentum and K.E. conserved.
  • Inelastic: Bodies stick together; only momentum conserved.
• Law of Conservation of Linear Momentum: Total momentum stays constant in a closed system.
• Friction: Opposes motion ($F_f = \mu F_n$). Reduced by rollers, ball bearings, and lubrication.

Work, Energy, Power, and Machines

• Work: Force $\times$ Distance ($J$).
• Power: Work done per unit time ($W$). $P = Fv$.
• Mechanical Energy: Potential ($mgh$) and Kinetic ($\frac{1}{2}mv^2$).
• Machines:
  • $\text{Mechanical Advantage (M.A.)} = \frac{\text{Load}}{\text{Effort}}$.
  • $\text{Velocity Ratio (V.R.)} = \frac{\text{Effort distance}}{\text{Load distance}}$.
  • $\text{Efficiency} = (\frac{\text{M.A.}}{\text{V.R.}}) \times 100$.
  • V.R. for Lever ($\frac{L_e}{L_l}$), Pulleys (number of strings), Wheel/Axle ($\frac{R}{r}$), Inclined Plane ($\frac{1}{\sin(\theta)}$), Screw ($\frac{2\pi r}{P}$).

Heat Quantity and Gas Laws

• Heat Capacity (C): Heat for $1^{\circ}C$ rise ($C = \frac{Q}{\theta}$).
• Specific Heat Capacity (c): Heat for $1\,kg$ rise ($Q = mc\theta$).
• Latent Heat: Energy for state change without temp change ($Q = mL$).
• The Gas Laws:
  1. Boyle's Law: $P_1 V_1 = P_2 V_2$ (constant Temp).
  2. Charles's Law: $\frac{V_1}{T_1} = \frac{V_2}{T_2}$ (constant Pressure).
  3. Pressure Law: $\frac{P_1}{T_1} = \frac{P_2}{T_2}$ (constant Volume).
  4. General Gas Law: $\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}$.

Thin Lenses and Optical Instruments

• Lens Formula: $\frac{1}{f} = \frac{1}{u} + \frac{1}{v}$.
• Magnification ($m$): $m = \frac{v}{u}$.
• Power of Lens: $P = \frac{1}{f}$ (Diopters, $D$).
• Instruments: Compound Microscope, Astronomical Telescope, Camera, Human Eye.
• Eye Defects: Myopia (short-sighted; use concave), Hypermetropia (long-sighted; use convex), Astigmatism (cylindrical lens).

Modern Physics and Electronics

• Cathode Rays: Streams of electrons in a vacuum. Discovered by J.J. Thomson. Used in CRO (Cathode Ray Oscilloscope).
• X-Rays: Produced by high-speed electrons hitting a metal target (Tungsten). $\text{Energy} = hf = eV$. Hard vs Soft X-rays depend on penetration.
• Photoelectric Effect: Emission of electrons from metals via light. $hf = \Phi + \frac{1}{2}mv^2_{\text{max}}$.
• Radioactivity: Spontaneous decay of unstable nuclei.
  • $\alpha$ (Helium nucleus), $\beta$ (electron), $\gamma$ (EM radiation).
  • Half-life: Time for half the sample to decay.
  • Fission: Splitting nuclei (Atomic bomb). Fusion: Combining nuclei (Hydrogen bomb).
• Electronics:
  • Semiconductors: Silicon, Germanium.
  • Doping: N-type (Donor/electrons) and P-type (Acceptor/holes).
  • Junction Diode: Conducts in forward bias; blocks in reverse bias. Used in Rectification (AC to DC).