Hertz

Examples of Hertz in the following topics:

• Maxwell's Predictions and Hertz' Confirmation

  • Maxwell's prediction of the electromagnetic force was confirmed by Hertz who generated and detected electromagnetic waves.
  • Hertz used an AC RLC (resistor-inductor-capacitor) circuit that resonates at a known frequency and connected it to a loop of wire as shown in .
  • The propogation of an electromagnetic wave as predicted by Maxwell and confirmed by Hertz.
  • The apparatus used by Hertz in 1887 to generate and detect electromagnetic waves.
  • Explain how Maxwell's prediction of the electromagnetic force was confirmed by Hertz

• Wavelength, Frequency, and Pitch

  • They measure it in hertz, which is how many peaks go by per second.
  • People can hear sounds that range from about 20 to about 17,000 hertz.
  • Most musicians cannot name the frequencies of any notes other than the tuning A (440 hertz).
  • The human ear can easily distinguish two pitches that are only one hertz apart when it hears them both, but it is the very rare musician who can hear specifically that a note is 442 hertz rather than 440.

• Frequency of Sound Waves

  • The SI unit of frequency is called a Hertz, denoted Hz.
  • A hertz is defined as the number of cycles per second.
  • Three flashing lights, from lowest frequency (top) to highest frequency (bottom). f is the frequency in hertz (Hz); or the number of cycles per second.

• Period and Frequency

  • In SI units, the unit of frequency is the hertz (Hz), named after the German physicist Heinrich Hertz: 1 Hz indicates that an event repeats once per second.
  • A traditional unit of measure used with rotating mechanical devices is revolutions per minute, abbreviated RPM. 60 RPM equals one hertz (i.e., one revolution per second, or a period of one second).

• Antennae

  • Maxwell's 1865 prediction passed an important test in 1888, when Heinrich Hertz published the results of experiments in which he showed that radio waves could be manipulated in the same ways as visible light waves.
  • To aid in his experiment, Hertz built the first antenna.

• Licensing

  • Holiday Inn, Hertz Car Rental, and McDonald's have all expanded into foreign markets through franchising.

• The Photoelectric Effect

  • Heinrich Hertz discovered the photoelectric effect in 1887.
  • Although electrons had  not been discovered yet, Hertz observed that electric currents were produced when ultraviolet light was shined on a metal.

• Aliasing

  • As we have seen, if a time-dependent function contains frequencies up to $1/2f_s$ hertz, then discrete samples taken at an interval of $1/2f_s$ seconds completely determine the signal.

• Photon Energies of the EM Spectrum

  • In 1886, the physicist Hertz built an apparatus to generate and detect what are now called radio waves, in an attempt to prove Maxwell's equations and detect such low-frequency electromagnetic radiation.
  • Hertz found the waves and was able to infer (by measuring their wavelength and multiplying it by their frequency) that they traveled at the speed of light.
  • Hertz also demonstrated that the new radiation could be both reflected and refracted by various dielectric media, in the same manner as light.

• Simple harmonic oscillation

  • Hz is Short for Hertz, after the German physicist Heinrich Hertz.
  • Hertz was born in Hamburg in 1857 and studied at the University of Berlin.
  • Hertz is best known as the first to broadcast and receive radio waves: a profoundly influential discovery.
  • Less well known is the fact that Hertz also discovered the photoelectric effect, while pursuing his research into radio waves.
  • A modest man, Hertz died at the age of 37 in 1894 from blood poisoning.