Hertz's Discovery of Radio Waves

• Who discovered the existence of radio waves?

  Heinrich Hertz
• What did Hertz create to generate radio waves?

  A short air gap with high voltage
• What was the purpose of the high voltage sparks in Hertz's experiment?

  To generate radio waves
• What equipment did Hertz use to detect radio waves?

  Circular wire and concave metal sheet
• How did the circular wire detect radio waves?

  It produced sparks across a break in the circuit
• What was the function of the concave metal sheet in Hertz's experiment?

  To induce oscillating potential difference
• What did Hertz demonstrate about radio waves using a metal screen?

  They could be reflected
• What was the significance of measuring a stronger signal with the detector?

  It showed radio waves were reflected
• What did Hertz find when an insulator was placed between the transmitter and detector?

  No difference in the signal detected
• How did Hertz demonstrate that radio waves were polarized?

  By rotating the detector 90°
• What caused the radio waves to be polarized according to Hertz?

  Electrons accelerated in one direction
• What crucial measurement did Hertz make regarding radio waves?

  The speed of the radio waves
• How did Hertz create a standing wave in his experiment?

  By reflecting radio waves off a flat metal sheet

  
• What did Hertz observe when passing a detector across the standing wave?

  Large signal at antinodes, none at nodes
• How did Hertz determine the wavelength of the radio waves?

  By measuring the distance between antinodes
• What equation did Hertz use to calculate the speed of radio waves?

  $v =$$f\lambda$
• What did Hertz's measurements confirm about radio waves?

  They are electromagnetic waves
• How can a radio wave transmitter, detector, and flat metal sheet be used to determine the speed of radio waves?

  1. The flat sheet reflects radio waves.
  2. Incident and reflected waves create interference.
  3. Standing wave forms with antinodes and nodes.
  4. Measure distance between antinodes for wavelength.
  5. Use $v =$$f\lambda$ to calculate speed.

  
• What are the key concepts related to Hertz's discovery of radio waves?

  • Generation of radio waves via high voltage sparks
  • Detection using circular wire and concave metal sheet
  • Reflection, penetration of insulators, and polarization of waves
  • Measurement of speed using standing waves and wave equation