Light Waves Module 2

Module Two

Light Waves

Electromagnetic Radiation

• Light is a type of electromagnetic radiation.

• Speed of light in empty space:

  • 300,000 km/s

  • Represented as 3 x 10^5 km/s

  • Denoted by the constant "c".

• Composed of particles known as photons, but exhibits wave properties.

• Electric and magnetic charges exhibit wave-like movement.

• Waves transmit energy without physically moving material.

Wave Characteristics

• Crest:

  • The highest point of a wave.

• Trough:

  • The lowest point of a wave.

• Wavelength:

  • Distance between successive crests or troughs.

  • Shorter wavelength = higher energy.

• Amplitude:

  • Maximum displacement of the wave from its undisturbed state.

  • Indicates the height of the wave.

  • Higher amplitude = greater disturbance.

Wave Period, Frequency, and Speed

• Wave Period:

  • Duration for one cycle of a wave to pass a specific point.

• Frequency:

  • Number of waves passing a point in one second.

  • Calculated as Frequency = 1 / Period

  • Measured in Hertz (Hz) or s⁻¹.

  • Higher frequency = more energy.

• Wave Speed:

  • Calculated as Wave Speed = Frequency x Wavelength.

Waves in What?

• Most waves require a medium to travel through:

  • Examples: Water, Air (Wind).

• Electromagnetic Waves:

  • Do not require a medium for propagation.

  • Travel at the speed of sound in a vacuum.

Diffraction and Interference

• Diffraction:

  • Bending of waves around obstacles.

• Interference:

  • The result of the summation of two waves.

  • Can result in a wave larger (constructive) or smaller (destructive) than the original waves.

Light as a Particle

• Photon Behavior:

  • Einstein demonstrated that light can behave as particles that carry energy.

  • Increased number of photons results in a brighter image.

  • Brighter images correspond to higher intensity.

  • Note: Intensity does not equate to energy.