Question

Every physical quantity has to have a dimension. True or false?

• A. True
• B. False

Answer 1

The correct option is B False

False. There are infinitely many dimensionless quantities and they are often called numbers. Few examples are:
Archimedes number (used in motion of fluids due to density differences), Decibel (used to calculate ratio of two intensities of sound), Pi (used in mathematics) etc.