Question

Among the following, the physical quantity without dimensional formula is          ​

Answer 1

Answer:

Dimensionless variables are those physical quantities which do not have dimensions and do not have a fixed value. For example Specific gravity, refractive index, the coefficient of friction, Poisson's ratio, etc.

Answer 2

Refractive index, numbers, Reynold's number strain, etc.

Explanation:

• Dimensionless quantity means a quantity which is independent of physical or fundamental units like mass, time, length etc.
• A dimensionless quantity is a quantity to which no physical dimension is assigned, also known as scalar quantity or a quantity of dimension one, with a corresponding unit of measurement in the SI of the unit one (or 1), which is not explicitly shown.

There are two types of dimensionless quantities:

1. Dimensionless variables - Physical quantities which has no dimensions but have variable values, Ex: specific gravity, refractive index etc.
2. Dimensionless constants - Quantities have constant values and also has no dimension. Ex: e, numbers etc.