Keith Davy Froome

from Wikipedia, the free encyclopedia

Keith Davy Froome (born February 11, 1921 in Istanbul , † October 24, 1995 ) was an English physicist .

In the 1940s and 1950s it was possible to measure the wavelength ( λ ) of light , but there was no precise way to determine the frequency ( ).

In the late 19th century, radio and microwaves enabled a new approach to measuring the speed of light . In 1888, more than 200 years after Rømer , the German physicist Heinrich Hertz was able to measure the speed of radio waves. Hertz came in at a rate close to 300,000 km per second, confirming James Clerk Maxwell 's theory that radio waves and light are two forms of the same electromagnetic radiation . Froome and Louis Essen were able to provide further confirmation between 1940 and 1950 by using microwaves or radio waves for measurement.

Froome interferometer

Froome generated an electromagnetic wave at 72 GHz and sent it through his interferometer . The microwaves were split into two beams and guided through two identical metal pipes to two detectors on a freely movable carriage. Changing the position of the car also changed the path length of the two beams, causing interference in the detectors. From this he was able to derive a wavelength of about 0.4 cm and calculated the speed of light with a value of 299,792.5 ± 0.3  km / s. Froome published its results in 1958.

In the late 1960s, lasers took over the generation of highly defined frequencies and wavelengths.

In 1961 Froome received the Wolfe Award, in 1963 the Moseley Prize; In 1967 he was awarded the Duddell Medal of the Institute of Physics London .

Fonts

  • KD Froome: The cathode mechanism of the vacuum arc with special reference to the condenser arc and mercury arc. Thesis (DIC) - Department of Physics, Imperial College, London 1947
  • KD Froome: Current densities of free-moving cathode spots on mercury . In: Brit. J. Appl. Phys. 4, 1953, pp. 91-92
  • KD Froome: An 8-volt cold-cathode mercury arc-emitting microwaves . In: Nature 179, 1957, pp. 267-268
  • KD Froome and L. Essen: The velocity of light and radio waves . Academic Press, London 1969, ISBN 0-12-242850-1

Individual evidence

  1. ^ Who's who in British science . 1953.
  2. ↑ Obituary Keith Davy Froome BSc DIC PhD DSc FInstP. In: tandfonline.com. Survey Review, 33: 260, pp. 391–392, accessed February 11, 2020.
  3. ^ The 1961 Wolfe Award: Dr. Keith Froome. In: Nature. 194, 1962, pp. 336-337, doi : 10.1038 / 194336c0 .
  4. ^ Moseley medal recipients
  5. ^ Gabor medal recipients
personal data
SURNAME Froome, Keith Davy
BRIEF DESCRIPTION English physicist
DATE OF BIRTH February 11, 1921
PLACE OF BIRTH Istanbul
DATE OF DEATH October 24, 1995