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Quality Factor 'Q' (Radiation)
It is a dimensionless variable weighing factor to be applied to the absorbed dose to provide an estimate of relative human hazard of different types and energies of ionizing radiations. Values of Q are selected from experimental values of relative biological effectiveness (RBE), which is ratio of 
X-ray or Gamma ray dose to that of radiation in question giving same kind and degree of biological effect. 

Quantum numbers
They are set of four numbers, the values of which are used to label possible electron states. Three of the quantum numbers are integers, which also specify the size, shape, and special orientation of an electrons probability density; the fourth number designates spin orientation.