. Radioactive transformations . case of the a rays thesecondary radiation consists of negatively charged particles(electrons) projected at velocities comparatively small com-pared with those of the ft particles themselves. The secondaryrays arising from the ft and 7 rays consist in part of electronsprojected with considerable velocity. These secondary rays inturn produce tertiary rays, and so on. HISTORICAL INTRODUCTION 21 If a strong magnetic field is applied at right angles to apencil of a, ft and 7 rays, the three types of rays are sepa-rated from each other. This is shown in Fig. 1, where
. Radioactive transformations . case of the a rays thesecondary radiation consists of negatively charged particles(electrons) projected at velocities comparatively small com-pared with those of the ft particles themselves. The secondaryrays arising from the ft and 7 rays consist in part of electronsprojected with considerable velocity. These secondary rays inturn produce tertiary rays, and so on. HISTORICAL INTRODUCTION 21 If a strong magnetic field is applied at right angles to apencil of a, ft and 7 rays, the three types of rays are sepa-rated from each other. This is shown in Fig. 1, where themagnetic field is acting downwards, perpendicular to the plain;of the paper. The /3 raysare bent to the right, the arays to the left, while the7 rays are unaffected. The/3 rays consist of particleshaving unequal velocitiesand consequently traversingcircular orbits of differentradii of curvature. Themagnetic deflection of thea rays compared with thatof the /3 rays is much exag-gerated in the figure. The relative mass, veloci. Fig. of radium rays by the action ty,and kinetic energy of the of a ma^netic field average a and £ particles are shown in Fig. 2, where the volume of a sphere represents mass and energy, and the length of line represents velocity. It will be seen from this illustration that although the average ft particle has a much higher velocity than the average a parti-cle, its energy of mo-tion on account of itsrelatively small massis much less thanthat of the average* /S particle. This re-sult is in accordancewith the observedresult that the ioni-zation and heating effect produced by the a particle are much greater than for the /3 particle. The writer has recently shown that one gram of radium in MASS VELOCITY ENERGY * O - ® 0 • ( @ 22 RADIOACTIVE TRANSFORMATIONS radioactive equilibrium emits about 7 x 1010 ft particles andabout X 1011 a particles per second. Four a particles arethus expelled from radium for each /3 particle. Radioactive Subst
Size: 1685px × 1482px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorrutherfo, bookcentury1900, bookdecade1900, bookyear1906
