Question

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 a unit.
(d) a constant which has no unit.

Answer 1

[A] Quantities having units, but no dimensions : Plane angle,angular displacement, solid angle.These physical quantities possess units but they does not possess dimensional formulas. 
B a physical quntatity neither having units nor dimensions are trigonometric ratios,strain , specific gravity etc.
C  a constant which has unit is planck constant etc

D a constant with no unit are 1,2,3 ....,etc

Answer 2

Answer:

[A] Quantities having units, but no dimensions : Plane angle,angular displacement, solid angle.These physical quantities possess units but they does not possess dimensional formulas. 

B a physical quntatity neither having units nor dimensions are trigonometric ratios,strain , specific gravity etc.

C  a constant which has unit is planck constant etc

D a constant with no unit are 1,2,3 ....,etc