# Fundamental vs Derived Quantity: Question and Answers

Dive into the fundamentals of measurement and understand the distinction between fundamental and derived quantities. Explore examples, differences, and the significance of these concepts in the world of science.

## Question 1:

Define fundamental quantities and provide examples.

Answer: Fundamental quantities are basic physical quantities that are independent and cannot be defined in terms of other quantities. They are the building blocks of the measurement system. Examples of fundamental quantities include length, mass, time, electric current, temperature, amount of substance, and luminous intensity.

## Question 2:

Differentiate between fundamental and derived quantities.

Answer: Fundamental quantities are the basic quantities that cannot be defined in terms of other quantities. Derived quantities, on the other hand, are obtained from the combination of fundamental quantities through mathematical operations or equations. Derived quantities are dependent on one or more fundamental quantities.

## Question 3:

Provide three examples of derived quantities and explain how they are derived.

Answer: i. Speed: Speed is a derived quantity, calculated by dividing the distance traveled by an object by the time taken. It is derived from the fundamental quantities of length and time.

ii. Volume: Volume is a derived quantity obtained by multiplying three lengths together (length × width × height). It is derived from the fundamental quantity of length.

iii. Acceleration: Acceleration is a derived quantity defined as the rate of change of velocity. It is obtained by dividing the change in velocity by the time taken. Acceleration is derived from the fundamental quantities of length and time.

## Question 4:

Why are fundamental quantities important in physics?

Answer: Fundamental quantities are important in physics because they form the foundation of the measurement system. All other quantities are derived from these fundamental quantities. They provide a consistent and universal basis for measuring and describing physical phenomena. By defining a set of fundamental quantities, it becomes possible to express and understand various physical phenomena in a standardized and systematic manner.

## Question 5:

Answer: Energy is a derived quantity. It is derived from the fundamental quantities of mass, length, and time. The SI unit of energy is the joule (J), which is defined as kg·m²/s². Energy can be calculated by multiplying the mass of an object by the square of its velocity, or by multiplying a force by the distance over which it acts. Therefore, energy is dependent on other fundamental quantities and is not considered a fundamental quantity itself.

## Question 6:

Explain the concept of dimensional analysis and its relevance to derived quantities.

Answer: Dimensional analysis is a technique used to check the consistency of equations and derive relationships between physical quantities. It involves analyzing the dimensions (units) of various quantities involved in a problem. In the context of derived quantities, dimensional analysis helps to determine the combination of fundamental quantities and their exponents that are required to derive a particular derived quantity.

## Question 7:

What are the advantages of using a system of fundamental quantities in scientific measurements?

Answer: Using a system of fundamental quantities provides a standardized and consistent framework for scientific measurements. It allows for clear and precise communication of measurements across different scientific disciplines and countries. It also enables the derivation and understanding of relationships between different physical quantities, facilitating the development of scientific theories and laws.

## Question 8:

Answer: Temperature is a fundamental quantity. It is one of the seven fundamental quantities in the SI system. Temperature is not derived from any other quantities but is measured independently using instruments like thermometers.

## Question 9:

What is the difference between base units and derived units in the SI system?

Answer: Base units are the units of measurement for the fundamental quantities in the SI system. They are independent and cannot be derived from other units. Derived units, on the other hand, are obtained by combining base units through mathematical operations or equations. Derived units are dependent on one or more base units.

## Question 10:

Explain the concept of dimensionless quantities and provide an example.

Answer: Dimensionless quantities are quantities that do not have any physical units associated with them. They are pure numbers. Examples of dimensionless quantities include ratios, such as the coefficient of friction, the fine structure constant in physics, or the aspect ratio of a shape.