Question

Poise is the unit of (a) viscosity (b) velocity (c) force (d) time

Short answer

The unit of poise is associated with viscosity. Thus, the correct answer is (a) viscosity.

Step-by-step solution

Understand the Units of Each Given Quantity

To determine which quantity is measured in the unit of poise, let's first recall the units of each of the given quantities: (a) Viscosity: its SI unit is Pascal-seconds (Pa·s), but other units are also used, such as the cgs (centimeter-gram-second) unit, which is poise (P). (b) Velocity: its SI unit is meters per second (m/s). (c) Force: its SI unit is Newton (N). (d) Time: its SI unit is the second (s).

Identify the Quantity with the Unit Poise

From our understanding of the units of each given quantity, we can conclude that the unit of poise is associated with viscosity. Therefore, the correct answer is: (a) viscosity

Key concepts

Units of Measurement

When working in the realm of science and engineering, understanding units of measurement is crucial. Units of measurement enable us to quantify and express physical quantities in a standardized way.
This standardization allows for clear communication and comparison both in academic settings as well as in practical applications. Units of measurement are often categorized by the type of quantity they describe. For example, the meter is the unit used to measure length, the second for time, and the kilogram for mass in the International System of Units (SI).
In the exercise, the unit of 'poise' is used, which belongs to the centimeter-gram-second (cgs) system, emphasizing the importance of not only understanding SI units but also being aware of other unit systems like cgs, frequently used in specific fields such as fluid dynamics.

Physical Quantities

Physical quantities are properties or characteristics of objects and systems that can be measured. Understanding physical quantities allows us to capture and describe features of the natural world.
They form the basis for many scientific laws and principles. Physical quantities can range from basic ones like length, mass, and time to more complex ones like velocity, force, and viscosity. Each of these has a specific unit of measurement, allowing people to express them numerically.
In essence, when dealing with exercises like identifying the unit of viscosity, it's crucial first to understand what physical quantity we are dealing with and how it relates to the corresponding unit. In our case, viscosity is a measure of a fluid's resistance to deformation or flow, which is specifically expressed in units such as Pascal-seconds in SI or poise in cgs.

Units of Viscosity

Viscosity is an important physical quantity in fluid mechanics. Understanding its units can provide a deeper insight into the behavior of liquids and gases.
Viscosity is the measure of a fluid's resistance to gradual deformation by shear or tensile stress. There are various units for measuring viscosity:

• In the International System of Units (SI), viscosity is expressed in Pascal-seconds (Pa·s).
• In the centimeter-gram-second (cgs) system, the unit used is poise (P). One poise is equivalent to 0.1 Pa·s.

The adoption of different units across different systems (SI vs. cgs) means understanding their correlations is crucial. Knowing how to convert between these units can be particularly helpful in scientific studies or engineering tasks that involve international collaboration or literature.