question_answer 62)

                  Give an example of                 (a) a physical quantity which has a unit but no             dimensions.                 (b) a physical quantity which has neither unit nor             dimensions.                 (c)  a constant which has unit.                 (d) a constant which has no unit.                

Answer:

                  (a) Angle or solid angle                 (b) Strain (longitudinal or volume) Poisson ratio, relative density                  (c) Speed of light in vacuum, Gravitational constant, Planck?s constant                 (d) Reynold number.