Physics

Introduction to Oscillations & EM Waves

Oscillations refer to repetitive variations, typically in time, of a physical quantity. Electromagnetic (EM) waves are waves of electric and magnetic fields oscillating perpendicular to each other and the direction of wave propagation.

Core Concepts

Simple Harmonic Motion

Motion in which the restoring force is proportional to displacement.

Resonance

When the frequency of driving force matches the natural frequency.

EM Waves

Waves consisting of oscillating electric and magnetic fields.

Important Equations

x(t) = A sin(ωt + φ)

SHM Equation

T = 2π√(m/k)

Mass-Spring Oscillator

c = fλ

Wave Equation

E/B = c

Relation in EM Waves

Types of Electromagnetic Waves

Radio Waves: Used in communication systems.
Microwaves: Used in cooking and radar.
Infrared: Used in night vision and heating.
Visible Light: The light detectable by the human eye.
Ultraviolet: Causes fluorescence and sunburn.
X-rays: Used in imaging bones.
Gamma Rays: High energy, used in cancer treatment.

Example Problems

1. A mass of 0.5 kg is attached to a spring of constant 200 N/m. Find the time period.

Solution: T = 2π√(0.5 / 200) ≈ 0.314 s

2. If EM wave has frequency 100 MHz, find its wavelength.

Solution: λ = c/f = 3×10⁸ / 100×10⁶ = 3 m

3. An object undergoes SHM with amplitude 4 cm and ω = 2 rad/s. Find max velocity.

Solution: vmax = Aω = 0.04 × 2 = 0.08 m/s