Speed of light demonstration using Doppler beat

From an apparatus previously designed for measuring the Doppler shift using a rotating mirror, an improved, versatile version was developed for speed of light demonstrations in a classroom or a teaching laboratory. By adding a second detector and adequate beam-splitter and mirrors, three different c...

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Autores principales: Bernal, L., Bilbao, L.
Formato: JOUR
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Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01430807_v39_n3_p_Bernal
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spelling todo:paper_01430807_v39_n3_p_Bernal2023-10-03T14:59:14Z Speed of light demonstration using Doppler beat Bernal, L. Bilbao, L. Doppler experiment optics speed of light Budget control Demonstrations Experiments Interferometry Light velocity Mirrors Optics Students Teaching Doppler Frequency beat Interferometric methods Rotating mirrors Rotation frequencies Teaching laboratories Time of flight measurements Undergraduate students Light From an apparatus previously designed for measuring the Doppler shift using a rotating mirror, an improved, versatile version was developed for speed of light demonstrations in a classroom or a teaching laboratory. By adding a second detector and adequate beam-splitter and mirrors, three different configurations are easily assembled. One configuration is used for time-of-flight measurements between a near and a far detector, allowing one to measure the speed of light provided that the path length between detectors is known. Another variation is the interferometric method obtained by superposing the far and near signals in such a way that a minimum of the combined signal is obtained when the time delay makes the signals arrive out of phase by π radians. Finally, the standard Doppler configuration allows the measurement of the frequency beat as a function of the rotation frequency. The main advantages of the apparatus are (a) the experimental setup is simple and completely accessible to undergraduate students, (b) the light is visible, students can see the rays, which, with the use of appropriate screens, can be blocked at any point along their paths, (c) the experiment can take place entirely within the teaching laboratory or demonstration room (using the interferometric method, the shortest distance to the far mirror was as small as 0.5 m), and (d) different configurations can be built, including some economical setups within the budget of teaching laboratories. © 2018 European Physical Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01430807_v39_n3_p_Bernal
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Doppler
experiment
optics
speed of light
Budget control
Demonstrations
Experiments
Interferometry
Light velocity
Mirrors
Optics
Students
Teaching
Doppler
Frequency beat
Interferometric methods
Rotating mirrors
Rotation frequencies
Teaching laboratories
Time of flight measurements
Undergraduate students
Light
spellingShingle Doppler
experiment
optics
speed of light
Budget control
Demonstrations
Experiments
Interferometry
Light velocity
Mirrors
Optics
Students
Teaching
Doppler
Frequency beat
Interferometric methods
Rotating mirrors
Rotation frequencies
Teaching laboratories
Time of flight measurements
Undergraduate students
Light
Bernal, L.
Bilbao, L.
Speed of light demonstration using Doppler beat
topic_facet Doppler
experiment
optics
speed of light
Budget control
Demonstrations
Experiments
Interferometry
Light velocity
Mirrors
Optics
Students
Teaching
Doppler
Frequency beat
Interferometric methods
Rotating mirrors
Rotation frequencies
Teaching laboratories
Time of flight measurements
Undergraduate students
Light
description From an apparatus previously designed for measuring the Doppler shift using a rotating mirror, an improved, versatile version was developed for speed of light demonstrations in a classroom or a teaching laboratory. By adding a second detector and adequate beam-splitter and mirrors, three different configurations are easily assembled. One configuration is used for time-of-flight measurements between a near and a far detector, allowing one to measure the speed of light provided that the path length between detectors is known. Another variation is the interferometric method obtained by superposing the far and near signals in such a way that a minimum of the combined signal is obtained when the time delay makes the signals arrive out of phase by π radians. Finally, the standard Doppler configuration allows the measurement of the frequency beat as a function of the rotation frequency. The main advantages of the apparatus are (a) the experimental setup is simple and completely accessible to undergraduate students, (b) the light is visible, students can see the rays, which, with the use of appropriate screens, can be blocked at any point along their paths, (c) the experiment can take place entirely within the teaching laboratory or demonstration room (using the interferometric method, the shortest distance to the far mirror was as small as 0.5 m), and (d) different configurations can be built, including some economical setups within the budget of teaching laboratories. © 2018 European Physical Society.
format JOUR
author Bernal, L.
Bilbao, L.
author_facet Bernal, L.
Bilbao, L.
author_sort Bernal, L.
title Speed of light demonstration using Doppler beat
title_short Speed of light demonstration using Doppler beat
title_full Speed of light demonstration using Doppler beat
title_fullStr Speed of light demonstration using Doppler beat
title_full_unstemmed Speed of light demonstration using Doppler beat
title_sort speed of light demonstration using doppler beat
url http://hdl.handle.net/20.500.12110/paper_01430807_v39_n3_p_Bernal
work_keys_str_mv AT bernall speedoflightdemonstrationusingdopplerbeat
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