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Wave-length of Electric Radiation by Diffraction Grating.
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Grating B.—Breadth of strip = 1·5 cm.
| i. | θ | λ | Mean for B. | |||||
| 38·0° 26·0 28·5 |
0° 10 8 |
1·847 1·836 1·849 |
1·844 | |||||
Grating C.—Breadth of strip = 2 cm.
| i. | θ | λ | Mean for C. | |||||
| 27·5° 22·0 20·0 |
0° 5 7 |
1·846 1·847 1·855 |
1·849 | |||||
Grating D.—Breadth of strip = 2·5 cm.
| i. | θ | λ | Mean for D. | |||||
| 21·5° 29·5 33·0 34·0 |
0° –7 –10 –11 |
1·832 1·852 1·854 1·841 |
1·845 | |||||
Grating E.—Breadth of strip = 3 cm.
| i. | θ | λ | Mean for E. | |||||
| 18·0° 23·25 25·5 31·0 |
0° –5 –7 –12 |
1·854 1·845 1·851 1·843 |
1·848 | |||||
It would thus be seen that the different values of wave-length obtained from the above experiments are concordant, the mean value being 1·846 cm.
I then carefully removed the electrical vibrator, and measured approximately the size of the sparking balls. The radiator, it must be remembered, was placed vertically inside a square tube, each of whose sides is 2·5 cm. The radiator was about 1 cm. inside from the free end of the tube.
