Question

Why poission’s ratio has no units.

Answer 1

Answer:

Because it's a ratio of two quantities will similar unit.So the units are cancelled out during the division.

For example:

Refractive index is the ratio of two quantities with same unit. So refractive index also don't have no unit.

Thank you

Answer 2

Answer:

Since we have different from of strain in the above equation and Dimensionless formula of strain=M0l0t0.And we know the ratio of Dimensionless quantity is Dimensionless. There fore poisson's ratio is Dimensionless and has no unit.