File:Crookes tube two views.jpg
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DescriptionCrookes tube two views.jpg |
English: Two photos of a Crookes tube; one by ordinary light and one showing it in operation lit by its own fluorescence. In operation several thousand volts of DC electricity is applied between the two electrodes in the tube. The electrode to the left is the cathode or negative electrode, the electrode in the L-shaped tube at bottom is the anode or positive electrode. Electrons released by the cathode are attracted toward the positive space charge in center of the tube, created by the positive anode at bottom, and they accelerate down the tube to the right. Because of inertia, many electrons speed past the anode rather than actually hitting it. They hit the glass wall of the tube, making the glass fluoresce green; after that, they eventually travel to the anode and leave the tube, passing through the wires and the power supply and back to the cathode. The cross-shaped metal plate blocks the electrons, casting a cross-shaped shadow on the glowing wall, demonstrating that the electrons travel in straight lines. The cross can be folded down against the floor of the tube, showing it is the cause of the shadow. The shadow can be moved and distorted by holding a permanent magnet to the side of the tube, demonstrating the bending effect that magnetic fields exert on electron rays. This 'Maltese cross' demonstration form of Crookes tube was first made by Juliusz Plucker in 1869, and was very popular in classrooms around the turn of the century. Alterations to image: Cropped component images and combined into one image. |
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Date | Taken on 29 March 2007 | |||||||
Source | File:Crookes tube-not in use-lateral view-standing cross prPNr°07.jpg and File:Crookes tube-in use-lateral view-standing cross prPNr°11.jpg | |||||||
Author | D-Kuru | |||||||
Permission (Reusing this file) |
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Other versions | Component images: File:Crookes tube-not in use-lateral view-standing cross prPNr°07.jpg, File:Crookes tube-in use-lateral view-standing cross prPNr°11.jpg |
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29 March 2007
2 second
3.2
6.142 millimetre
image/jpeg
7567014304494e273ba7ff2c79bb2a4b36bbdecd
524,554 byte
2,115 pixel
2,022 pixel
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 17:58, 7 May 2008 | 2,022 × 2,115 (512 KB) | wikimediacommons>Chetvorno | {{Information |Description=Two photos of a Crookes tube; one by ordinary light and one showing it in operation lit by it's own fluorescence. Alterations to image: Cropped component images and combined into one image. |Source=[[:Image:Schattenkreuzröhr |
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