What is Physical Quantity | Types, Definition & Examples

Introduction

In physics fundamentals, physical quantities are very important for understanding the natural world. A physical quantity is anything that can be measured and expressed with a number and a unit. Examples include length, mass, and time. These quantities help students describe motion, forces, and energy. Without physical quantities, science cannot be measured, calculated, or understood in a meaningful way.

Definition of Physical Quantity

Definition

A physical quantity is a property of a body or phenomenon that can be measured and written in numerical form with a unit.

Examples:

• Length = 10 meters
• Mass = 5 kilograms
• Time = 20 seconds

Formula Idea:

Physical Quantity = Numerical Value × Unit

👉 Example:
Distance = 15 m

📊 Infographic: What is a Physical Quantity?

🔹 Measurable → ✔
🔹 Has Number → ✔
🔹 Has Unit → ✔
🔹 Used in Science → ✔

Types of Physical Quantities

Physical quantities are mainly divided into two types:

Basic Quantities

These are independent quantities that cannot be derived from others.

Derived Quantities

These are formed by combining basic quantities using formulas.

📊 Infographic: Types of Physical Quantities

Physical Quantity

       │

 ┌─────┴─────┐

Basic      Derived

Basic Quantities with Table

Definition

Basic quantities are fundamental quantities in physics fundamentals that are not made from other quantities.

📊 Table of Basic Quantities

Derived Quantities with Formulas

Definition

Derived quantities are physical quantities that depend on basic quantities and are calculated using formulas.

📊 Table of Derived Quantities

📌 Important Formulas

• Speed = Distance ÷ Time
• Force = Mass × Acceleration
• Density = Mass ÷ Volume

Measurement of Physical Quantity

Definition

Measurement is the process of comparing a physical quantity with a standard unit.

📌 Measuring Instruments

• Ruler → Length
• Stopwatch → Time
• Weighing balance → Mass
• Thermometer → Temperature

📊 Steps of Measurement

1. Select a standard unit
2. Use correct instrument
3. Measure value carefully
4. Write number with unit

📊 Infographic: Measurement Process

Select Unit → Measure → Record → Write Answer

Importance in Physics Fundamentals

Physical quantities are the foundation of physics fundamentals. They help us understand motion, forces, energy, and natural laws. Without them, scientific calculations are impossible. They are used in daily life like measuring distance, time, and weight. Engineers, doctors, and scientists depend on physical quantities for accurate results and practical applications in real-world problem solving.

15 MCQs on Physical Quantity (With Answers)

1. What is a physical quantity?
A) A guess
B) A measurable quantity with unit
C) A color
D) A shape
✅ Answer: B

2. Which one is a basic quantity?
A) Speed
B) Force
C) Mass
D) Density
✅ Answer: C

3. Which one is a derived quantity?
A) Time
B) Length
C) Mass
D) Speed
✅ Answer: D

4. Which of the following is used to measure time?
A) Ruler
B) Stopwatch
C) Thermometer
D) Balance
✅ Answer: B

5. Physical quantity always has:
A) Color
B) Shape
C) Number and unit
D) Taste
✅ Answer: C

6. Unit of mass is:
A) meter
B) second
C) kilogram
D) liter
✅ Answer: C

7. Which is not a basic quantity?
A) Time
B) Length
C) Force
D) Mass
✅ Answer: C

8. Speed is calculated by:
A) Mass × Time
B) Distance ÷ Time
C) Time ÷ Distance
D) Force ÷ Mass
✅ Answer: B

9. Unit of speed is:
A) kg
B) m/s
C) N
D) J
✅ Answer: B

10. Which instrument measures length?
A) Stopwatch
B) Thermometer
C) Ruler
D) Barometer
✅ Answer: C

11. Derived quantities are formed by:
A) Addition of colors
B) Combination of basic quantities
C) Guessing
D) Writing words
✅ Answer: B

12. Force is a:
A) Basic quantity
B) Derived quantity
C) Scalar only
D) None
✅ Answer: B

13. Unit of time is:
A) meter
B) second
C) kilogram
D) ampere
✅ Answer: B

14. Density formula is:
A) mass × volume
B) mass ÷ volume
C) volume ÷ mass
D) force ÷ area
✅ Answer: B

15. Physical quantities are important in:
A) Cooking only
B) Physics fundamentals
C) Drawing only
D) Music
✅ Answer: B

15 Short Questions with Answers

1. What is a physical quantity?
A physical quantity is a measurable property that has a number and a unit.

2. Give two examples of physical quantities.
Length and mass are examples of physical quantities.

3. What are basic quantities?
Basic quantities are independent quantities that are not derived from others.

4. Name three basic quantities.
Length, mass, and time are basic quantities.

5. What are derived quantities?
Derived quantities are formed by combining basic quantities using formulas.

6. Give two examples of derived quantities.
Speed and force are examples of derived quantities.

7. What is the unit of length?
The unit of length is meter (m).

8. What is measurement?
Measurement is the process of comparing a quantity with a standard unit.

9. Name an instrument used to measure time.
A stopwatch is used to measure time.

10. Write the formula of speed.
Speed = Distance ÷ Time

11. Write the formula of force.
Force = Mass × Acceleration

12. What is the unit of force?
The unit of force is Newton (N).

13. Why are physical quantities important?
They help in measuring, comparing, and understanding scientific laws.

14. What is the unit of mass?
The unit of mass is kilogram (kg).

15. What do physics fundamentals study using physical quantities?
They study motion, force, energy, and other natural phenomena using physical quantities.

Conclusion

In physics fundamentals, physical quantities are essential for learning science in a clear and structured way. They allow us to measure, compare, and understand natural phenomena. Basic and derived quantities together form the base of all physics concepts. By studying them, students can easily solve problems and understand real-life applications. Physical quantities make science meaningful, accurate, and easy to apply.