The Becquerel rays and the properties of radium / by R.J. Strutt.

  • Rayleigh, Robert John Strutt, Baron, 1875-1947.
Date:
1906
Catalogue details

Licence: Public Domain Mark

Credit: The Becquerel rays and the properties of radium / by R.J. Strutt. Source: Wellcome Collection.

Provider: This material has been provided by the Francis A. Countway Library of Medicine, through the Medical Heritage Library. The original may be consulted at the Francis A. Countway Library of Medicine, Harvard Medical School.

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    ■where r is the radius of the circular path, and m the mass of the particle. Thus hev = , r ^r m , . or Ur = — V (1). e ^ ' Let us now consider the deflection of the rays by a uniform electrostatic force, at right angles to their initial direction. The motion is exactly the same as that of a horizontal pro- jectile, acted on by gravity, if the resistance of the air be neglected; for the electrostatic force produces a uniform acceleration of the particle at right angles to the initial direction of motion, and the path is in consequence a parabola, just as in the case of gravity. Let I be the length of the electrostatic field. Then the time taken by the particle to travel along it will be —. The force acting on the particle is equal to Fe, if F is the intensity of . Fe the field. The acceleration is —. Thus if cZ is the sideways displacement of the beam d=^\F-''- ^4-•••(2). Multiplying equations (1) and (2) together, we have ^ V Fl'' or V = 2Hrd Now all the quantities in terms of which v is expressed can be determined. Thus the strength of the magnetic field [H) and the radius of curvature it produces (r) can be measured. The strength [F] and length [I) of the electrostatic field can be measured too, as can also the sideways displacement d of the beam which it produces. Thus -y, the velocity of the cathode rays, is quite determinate. Knowing v, we can readily find — ; for, by equation (1), e _ V TYh ~ Hr This is not the only way in which these quantities {v and