Difference between a unitless and a dimensionless quantity? | neet physics | beat d neet| msd sir

The following is a unitless and dimensionless quantity

Which one of the following is dimensionless physical quantity?

STATEMENT 1: Two quantities with different dimensions may have same unit. STATEMENT-2 Two quantities with different units may have same dimensions STATEMENT-3 Unitless quantities must be dimensionless too

A unitless quantity is dimensionless. Is the statement true? If yes, explain.

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A, B, C and D are four different physical quantities having different dimensions. None of them is dimensionless. But we know that the equation AD= C 1n(BD) holds true. Then which of the combination is not a meaningful quantity :-

A : A unitless physical quantity must be dimensionless. R : A pure number is always dimensionless.

A : A dimensionless quantity may have unit. R : Two physical quantities having same dimensions, may have different units.

Do all physical quantities have dimensions? If no, name three physical quantities which are dimensionless.