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can a physical quantity be of different physical dimension depending on the system of measurement?

Yes, most definitely! The dimension of a physical quantity is a matter of convention which is established by the system of units. It is not a fundamental physical fact of the universe.

You have discovered this fact in the context of geometrized units which have only a single physical dimension, length. Geometrized units are the most extreme example of this, but is not commonly used so it is relatively obscure. However, the various “cgs” systems of units are commonly used but also have surprising variations in the dimensionality of electromagnetic quantities.

For example, the statcoulomb is the unit of charge in the cgs “Gaussian” units. Although the coulomb is the SI unit of charge, there is no direct conversion possible between the two. The Coulomb has dimensions of charge, Q, but the statcoulomb has dimensions of $L^{3/2} M^{1/2} T^{-1}$.

As a result the equations of electromagnetism are different in SI than in Gaussian units. In particular, Coulomb’s law in Gaussian units is $$F=\frac{q_1 q_2}{r^2}$$ in contrast to the usual expression in SI units $$F=\frac{1}{4\pi\epsilon_0}\frac{q_1 q_2}{r^2}$$

So the dimensionality of the physical quantity is a convention that is specified by the system of units used, and that convention will alter the mathematical form of the laws of physics when expressed in those units. At least regarding the presence of dimensionful constants.

Is it really the case? ... What does this table actually says?

Yes, that is really the case. That table actually says what it appears to be saying at face value. The physical dimensions of the geometrized units is different from the dimensionality of the corresponding SI quantities.

can a physical quantity be of different physical dimension depending on the system of measurement?

Yes, most definitely! The dimension of a physical quantity is a matter of convention which is established by the system of units. It is not a fundamental physical fact of the universe.

You have discovered this fact in the context of geometrized units which have only a single physical dimension, length. Geometrized units are the most extreme example of this, but is not commonly used so it is relatively obscure. However, the various “cgs” systems of units are commonly used but also have surprising variations in the dimensionality of electromagnetic quantities.

For example, the statcoulomb is the unit of charge in the cgs “Gaussian” units. Although the coulomb is the SI unit of charge, there is no direct conversion possible between the two. The Coulomb has dimensions of charge, Q, but the statcoulomb has dimensions of $L^{3/2} M^{1/2} T^{-1}$.

As a result the equations of electromagnetism are different in SI than in Gaussian units. In particular, Coulomb’s law in Gaussian units is $$F=\frac{q_1 q_2}{r^2}$$ in contrast to the usual expression in SI units $$F=\frac{1}{4\pi\epsilon_0}\frac{q_1 q_2}{r^2}$$

So the dimensionality of the physical quantity is a convention that is specified by the system of units used, and that convention will alter the mathematical form of the laws of physics when expressed in those units. At least regarding the presence of dimensionful constants.

can a physical quantity be of different physical dimension depending on the system of measurement?

Yes, most definitely! The dimension of a physical quantity is a matter of convention which is established by the system of units. It is not a fundamental physical fact of the universe.

You have discovered this fact in the context of geometrized units which have only a single physical dimension, length. Geometrized units are the most extreme example of this, but is not commonly used so it is relatively obscure. However, the various “cgs” systems of units are commonly used but also have surprising variations in the dimensionality of electromagnetic quantities.

For example, the statcoulomb is the unit of charge in the cgs “Gaussian” units. Although the coulomb is the SI unit of charge, there is no direct conversion possible between the two. The Coulomb has dimensions of charge, Q, but the statcoulomb has dimensions of $L^{3/2} M^{1/2} T^{-1}$.

As a result the equations of electromagnetism are different in SI than in Gaussian units. In particular, Coulomb’s law in Gaussian units is $$F=\frac{q_1 q_2}{r^2}$$ in contrast to the usual expression in SI units $$F=\frac{1}{4\pi\epsilon_0}\frac{q_1 q_2}{r^2}$$

So the dimensionality of the physical quantity is a convention that is specified by the system of units used, and that convention will alter the mathematical form of the laws of physics when expressed in those units. At least regarding the presence of dimensionful constants.

Is it really the case? ... What does this table actually says?

Yes, that is really the case. That table actually says what it appears to be saying at face value. The physical dimensions of the geometrized units is different from the dimensionality of the corresponding SI quantities.

Source Link
Dale
  • 109k
  • 11
  • 160
  • 319

can a physical quantity be of different physical dimension depending on the system of measurement?

Yes, most definitely! The dimension of a physical quantity is a matter of convention which is established by the system of units. It is not a fundamental physical fact of the universe.

You have discovered this fact in the context of geometrized units which have only a single physical dimension, length. Geometrized units are the most extreme example of this, but is not commonly used so it is relatively obscure. However, the various “cgs” systems of units are commonly used but also have surprising variations in the dimensionality of electromagnetic quantities.

For example, the statcoulomb is the unit of charge in the cgs “Gaussian” units. Although the coulomb is the SI unit of charge, there is no direct conversion possible between the two. The Coulomb has dimensions of charge, Q, but the statcoulomb has dimensions of $L^{3/2} M^{1/2} T^{-1}$.

As a result the equations of electromagnetism are different in SI than in Gaussian units. In particular, Coulomb’s law in Gaussian units is $$F=\frac{q_1 q_2}{r^2}$$ in contrast to the usual expression in SI units $$F=\frac{1}{4\pi\epsilon_0}\frac{q_1 q_2}{r^2}$$

So the dimensionality of the physical quantity is a convention that is specified by the system of units used, and that convention will alter the mathematical form of the laws of physics when expressed in those units. At least regarding the presence of dimensionful constants.