. The Becquerel rays and the properties of radium . tically the behaviour ofthe three kindsof rays in amagnetic a-rays, giv-ing rise to byfar the greaterpart of theelectrical effect,are slightly de-flected by atransverse mag-netic force, HI Pig. 20.—Diagram illustrative of tliB beliavioiir of tlie llii-oo that direCtlOUvarieties of Becqiierel rays in a field of magnetic force. The a- rays are bent very sli^^litly ill one direction. The ^-rays are bent wl;i^i(;;li COrre- very mnch in ttie oitpositc direction; while the y-rays are nut ^°- spends to an emission of positively charged mas
. The Becquerel rays and the properties of radium . tically the behaviour ofthe three kindsof rays in amagnetic a-rays, giv-ing rise to byfar the greaterpart of theelectrical effect,are slightly de-flected by atransverse mag-netic force, HI Pig. 20.—Diagram illustrative of tliB beliavioiir of tlie llii-oo that direCtlOUvarieties of Becqiierel rays in a field of magnetic force. The a- rays are bent very sli^^litly ill one direction. The ^-rays are bent wl;i^i(;;li COrre- very mnch in ttie oitpositc direction; while the y-rays are nut ^°- spends to an emission of positively charged masses. Measure-ments of the ratio of charge to mass suggest thatthey are comparable in mass to hydrogen or heliumatoms. The ;S-rays, which are principally instrumental inproducing the photographic effect, are deflected inthe opposite direction to the a-rays, and consist ofnegatively chai-ged corpuscles of much less thanatomic dimensions. The y-rays, not deflected at all by magnetic force,are probably Rontgen rays, produced by the CHAPTER IV ABSORPTION AND lONISATION We have already seen that the three varieties ofrays emitted by radium can be separated by meansof solid screens. Very thin screens allow all threekinds of rays to pass. Screens of moderate thicknesssuppress the a-rays, leaving the /3- and y-rays. Verythick screens allow the y-rays only to pass. It isnow time to consider the absorption of the rays bysolids somewhat more in detail. For studying the a-rays, it is convenient to makeuse of polonium. For polonium emits these raysonly, and the effects are not complicated by thepresence of the other kinds. In the first place, the a-rays are absorbed withextraordinary facility by the air. For they can onlypenetrate for a very small distance in the air—notmore than two inches, if so much. It was found by Mme. Curie that the percentageof the polonium rays, transmitted through a leaf ofaluminium ^hij miHinietre thick, was greater whenthe rays had to traver
Size: 1655px × 1510px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectradioac, bookyear1904
