Question

A dimensionless physical quantity but having unit in si system.

Answer 1

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Answer 2

Answer:

Radian is a dimension-less physical quantity and it's SI unit is 'rad'.

Explanation:

Dimension is the power to which a physical quantity is raised in terms of the fundamental quantities.

e.i.

$speed = \frac{distance}{time} = \frac{l}{t} = l {t}^{ - 1}$

Similarly,

Radian is the SI unit of angle.

$rad = \frac{arc \: lenght}{radius} = \frac{l}{l} = 1$

1 is dimension-less.

Conclusion:

Since 1 has no dimensions.

Therefore, radian is a dimension-less physical quantity but has a SI unit called 'rad'.