La interacció d' un feix que no toca una bola exactament, però toca un costat d' una, s' anomena "desviament". L' angle de desviament del feix és sempre 90 graus. Exemple: La bola mostrada podria desviar el feix "2" cap amunt, com es mostra, però aquesta no és la única possibilitat.
The interaction of a beam that does not actually hit a ball, but aims to one side of it, is called a "deflection". The angle of deflection of the beam is always 90 degrees. Example: The ball shown would deflect beam "2" upward, as shown, but this is not the only possibility.