FSC Part 2 Physics Notes - MatricNotes

MatricNotes

Chapter 1: Alternating Current

AC vs DC

DC: Direct current, constant direction
AC: Alternating current, changes direction periodically

Peak and RMS Values

I_rms = I_peak / √2
V_rms = V_peak / √2

AC Circuit Elements

Pure Resistor

V = IR (Ohm's law applies)

Pure Inductor

V = IX_L
X_L = ωL (Inductive reactance)

Pure Capacitor

V = IX_C
X_C = 1/ωC (Capacitive reactance)

RLC Series Circuit

Z = √(R² + (X_L - X_C)²)
I = V/Z
Power = VI cosφ (cosφ = power factor)

Resonance

When X_L = X_C, impedance minimum, current maximum.

f_r = 1/2π√(LC)

Chapter 2: Physics of Solids

Elastic Properties

Stress

Stress = Force / Area
Unit: N/m² (Pa)

Strain

Strain = Change in Dimension / Original Dimension
(Dimensionless)

Hooke's Law

Stress ∝ Strain
Stress = E × Strain
E = Young's Modulus

Types of Moduli

Young's Modulus (E): Tensile/compressive stress
Bulk Modulus (K): Volume stress
Shear Modulus (G): Shear stress

Energy in Stretched Wire

U = ½ × Stress × Strain × Volume

Chapter 3: Electronics

Semiconductors

Conductivity between conductors and insulators.

Intrinsic

Pure semiconductors (Si, Ge)

Extrinsic

n-type: Donor impurities (P, As) - extra electrons
p-type: Acceptor impurities (B, Al) - holes

p-n Junction

Junction between p-type and n-type semiconductor.

Forward Bias

p-side connected to positive, n-side to negative. Current flows.

Reverse Bias
p-side connected to negative, n-side to positive. No current (except leakage).

Diodes

Rectifier: Converts AC to DC
Zener: Voltage regulation
LED: Light emission
Photodiode: Light detection

Transistors

Three regions: Emitter, Base, Collector.

n-p-n: Common type
p-n-p: Alternative

Configurations

Common Emitter: Most common, voltage gain
Common Base: Current gain
Common Collector: Impedance matching

Chapter 4: Electromagnetic Waves

Maxwell's Equations

Electric field diverges from charges
Magnetic field has no divergence (no magnetic monopoles)
Changing magnetic field induces electric field
Current or changing electric field induces magnetic field

EM Wave Equation

c = 1/√(μ₀ε₀)
c = fλ
c = 3 × 10⁸ m/s

EM Spectrum

Radio: Communication
Microwave: Radar, cooking
Infrared: Heat, remote controls
Visible: Light we see
Ultraviolet: Sunburn, sterilization
X-rays: Medical imaging
Gamma rays: Nuclear reactions

Properties of EM Waves

Transverse nature
No medium required
Speed = c in vacuum
Obey superposition principle

Chapter 5: Modern Physics

Photoelectric Effect

Electrons emitted when light strikes metal.

Einstein's Equation

E = hf - φ
E = Kmax
Where: h = 6.626 × 10⁻³⁴ Js (Planck's constant)

Threshold Frequency

Minimum frequency for emission: f₀ = φ/h

Compton Effect

Photon scatters off electron, wavelength increases.

Wave-Particle Duality

Light behaves as wave (interference, diffraction) and particle (photoelectric effect).

de Broglie Wavelength

λ = h/p = h/mv

Heisenberg Uncertainty Principle

Δx × Δp ≥ h/4π

Chapter 6: Atomic Spectra

Bohr's Atomic Model

Electrons revolve in discrete orbits (stationary states).

Energy Levels

E_n = -13.6 eV / n²

Photon Emission

E_i - E_f = hf

Hydrogen Spectrum

Lyman Series: UV (n → 1)
Balmer Series: Visible (n → 2)
Paschen Series: IR (n → 3)

Quantum Numbers

n (Principal): 1, 2, 3...
l (Azimuthal):0 to n-1

m (Magnetic ): -l to +l
s (Spin): +½ or -½

Pauli Exclusion Principle

No two electrons in an atom can have same set of 4 quantum numbers.

Chapter 7: Nuclear Physics

Nucleus Composition

Protons: Z (atomic number)
Neutrons: N
Mass Number: A = Z + N

Isotopes

Same Z, different A.

Radioactivity

Alpha Decay

ᴬX → ᴬ⁻⁴Y + ₂He⁴

Beta Decay

ⁿ¹p → ¹₀n + ₋₁e⁰ + ν̄

Gamma Decay

Energy release without particle emission

Half-Life

N = N₀(1/2)^(t/T)

Mass Defect and Binding Energy

Δm = [Z(m_p) + N(m_n) - M]c²
E = Δmc²

Nuclear Reactions

Fission: Splitting (U-235, Pu-239)
Fusion: Combining (H → He in sun)