Question

A dimensionless quantity
(a) never has a unit, (b) always has a unit,
(c) may have a unit, (d) does not exist.

Answer 1

Please give example too.

Answer 2

radians are dimensionless because they are defined in terms of length/length
(circumference/diameter)

Answer 3

\[\pi\text{ radians }={C\cancel{\text{ meters}}\over d\cancel{\text{ meters}}}\]so the units cancel

Answer 4

thanx i gt it
but wt about this plz?
this is last one!

A unitless quantity
(a) never has a nonzero dimension,
(b) always has a nonzero dimension,
(c) may have a nonzero dimension,
(d) does not exist.

Answer 5

if it is unitless then the dimensions \(must\) cancel

Answer 6

so is 'a' right??

Answer 7

right :)

Answer 8

thanx a lot:D