CBSE Class 11-science Answered

Absorbers are used to slow down or retard charged particles. As a charged particle passes near an electron in the absorber, it transfers a small fraction of its momentum to the electron. As a result, the charged particle slows down slightly, and the electron (which originally was nearly at rest) picks up some of its kinetic energy. At any given time, the charged particle is simultaneously interacting with many electrons in the absorber material, and the net result of all the Coulomb forces acts like a viscous drag on the particle. From the instant it enters the absorber; the particle slows down continuously until it is brought to a stop.