Notes on Electromagnetic Radiation, Photoelectric Effect, and Polarization

Electromagnetic Radiation

• Speed of Electromagnetic Radiation in Vacuum

  • Electromagnetic radiation travels at a speed of approximately $c = 3.00 \times 10^8 \text{ m/s}$ in a vacuum.

Photoelectric Effect

• Evidence of Particle Properties of Light

  • The photoelectric effect demonstrates that light has properties of particles, specifically in how it interacts with matter.

  • When light hits certain substances, it can cause electrons to be ejected from those substances, indicating that light delivers energy in discrete packets or "quanta".

  • These packets are referred to as photons, reinforcing the particle theory of light.

Polarization of Light

• Wave Properties Demonstrated by Polarizing Filters

  • The use of two polarizing filters can be used to experimentally show the wave properties of light.

  • When light passes through the first polarizing filter, it becomes polarized, aligning the light waves in one direction.

  • The second polarizing filter can be oriented at varying angles to the first.

  • If the second filter is aligned in the same direction as the first, light will pass through.

  • If misaligned, light intensity decreases or is blocked depending on the angle, indicating wave characteristics such as interference and superposition.

Vocabulary Building

• Choose appropriate terms to complete sentences:

  5. The energy transferred by electromagnetic waves is called electromagnetic radiation.

  6. The photon hits some substances.

  7. A(n) photoelectric effect occurs when light causes electrons to move when it is a particle of light energy.

  8. Light that has passed through polarizing filters is polarized light.

  9. A(n) electromagnetic wave consists of changing electric and magnetic fields.