The correct option is **C. Velocity**. ### Detailed Explanation 1. **Understanding Derived Quantities**: - In physics, quantities can be classified into two main categories: **base quantities** and **derived quantities**. - **Base quantities** are fundamental physical quantities that cannot be expressed in terms of other quantities. Examples include mass, length, time, electric current, temperature, amount of substance, and luminous intensity. - **Derived quantities**, on the other hand, are those that can be expressed as combinations of base quantities. They are derived from the base quantities through mathematical relationships. 2. **Analyzing the Options**: - **A. Mass**: This is a base quantity. It is one of the fundamental measurements in physics and is not derived from other quantities. - **B. Time**: This is also a base quantity. Like mass, time is fundamental and does not depend on other measurements. - **C. Velocity**: This is a derived quantity. Velocity is defined as the rate of change of displacement with respect to time. Mathematically, it can be expressed as: \[ \text{Velocity} (v) = \frac{\text{Displacement} (s)}{\text{Time} (t)} \] Here, displacement is a measure of length (a base quantity), and time is a base quantity. Therefore, velocity is derived from these two base quantities. - **D. Temperature**: This is also a base quantity. It is a measure of the average kinetic energy of particles in a substance and is not derived from other quantities. 3. **Why Other Options Are Incorrect**: - **A. Mass**: As mentioned, mass is a fundamental quantity and does not depend on other measurements. It is a base quantity. - **B. Time**: Time is another fundamental measurement in physics. It is essential for defining many other concepts but is not derived from any other quantities. - **D. Temperature**: Temperature is a measure of thermal energy and is considered a base quantity in the International System of Units (SI). It is not derived from other quantities. ### Common Pitfalls - Students often confuse derived quantities with base quantities, especially when they involve common physical concepts. Remember that derived quantities are formed from combinations of base quantities. - It’s important to remember the definitions of each quantity and their relationships to avoid misclassifying them. ### Revision Summary - **Base quantities** are fundamental and cannot be derived from other quantities (e.g., mass, time, temperature). - **Derived quantities** are formed from base quantities (e.g., velocity is derived from displacement and time). - Always check the definitions and relationships between quantities to classify them correctly. - Remember that velocity is a measure of how fast something is moving and is calculated using displacement and time.