Physics – 5.2.2 The three types of nuclear emission | e-Consult

Alpha Particles: Alpha particles (⁴He nuclei, charge +2e, mass approximately 4 amu) are relatively massive and have a positive charge. When an alpha particle enters a uniform electric field, it is deflected towards the negative plate. The magnitude of the deflection is directly proportional to the charge of the particle (greater charge, greater deflection) and inversely proportional to its mass (less mass, greater deflection). The stronger the electric field, the greater the deflection. The deflection is also affected by the velocity of the alpha particle; a higher velocity results in a larger deflection.

When an alpha particle enters a uniform magnetic field, it experiences a force perpendicular to both its velocity and the magnetic field. This causes the alpha particle to move in a curved path. The direction of the deflection can be determined using the right-hand rule (thumb points in the direction of velocity, fingers point in the direction of the magnetic field, and the direction your palm faces is the direction of the force). The magnitude of the deflection is proportional to the charge of the particle, the speed of the particle, and the strength of the magnetic field. The mass of the particle is also a factor; a heavier particle will be deflected less. A higher velocity will result in a larger radius of curvature.

Beta Particles: Beta particles (e^- or e⁺, charge -1e or +1e, mass approximately 1/1836 amu) are electrons or positrons, respectively. They behave similarly to alpha particles in electric fields, being deflected towards the positive plate. The factors affecting deflection are the same as for alpha particles: charge, mass, and electric field strength.

In magnetic fields, beta particles also experience a curved path. The direction of deflection is again determined by the right-hand rule. The magnitude of the deflection is proportional to the charge, speed, and magnetic field strength, and inversely proportional to the mass. Because beta particles are much lighter than alpha particles, they are deflected more significantly by the magnetic field.

Gamma Radiation: Gamma radiation consists of photons, which are uncharged particles. Therefore, gamma radiation is not deflected by an electric or magnetic field. This is because the force on a charged particle is given by F = q(E + v x B), and since q = 0 for a photon, the force is zero. Gamma radiation travels in a straight line.