The correct option is **C. Displacement**. ### Detailed Explanation 1. **Understanding Scalars and Vectors**: - In physics, quantities are classified into two categories: scalars and vectors. - **Scalars** are quantities that have only magnitude (size) and no direction. Examples include temperature, speed, and time. - **Vectors**, on the other hand, have both magnitude and direction. Examples include displacement, velocity, and force. 2. **Analyzing Each Option**: - **A. Temperature**: - Temperature is a scalar quantity. It is measured in degrees (Celsius, Fahrenheit, Kelvin) and indicates how hot or cold an object is. It does not have a direction associated with it. - **B. Speed**: - Speed is also a scalar quantity. It measures how fast an object is moving, expressed in units like meters per second (m/s). Like temperature, speed does not have a direction; it only tells you how much distance is covered over time. - **C. Displacement**: - Displacement is a vector quantity. It refers to the change in position of an object and is defined as the shortest distance from the initial position to the final position, along with the direction of that line. Displacement can be positive, negative, or zero, depending on the direction of movement relative to a reference point. - **D. Time**: - Time is a scalar quantity. It measures the duration of events and is expressed in units like seconds, minutes, or hours. Time does not have a direction; it simply indicates when an event occurs. 3. **Why Other Options Are Incorrect**: - **Temperature (A)**: Lacks direction; it only tells us how hot or cold something is. - **Speed (B)**: While it tells us how fast something is moving, it does not indicate the direction of that movement. - **Time (D)**: Measures the duration of events without any directional component. ### Formulas and Concepts - **Displacement Formula**: \[ \text{Displacement} = \text{Final Position} - \text{Initial Position} \] - This formula shows that displacement is concerned with the difference in position, which inherently includes direction. ### Common Pitfalls - Students often confuse speed with velocity. Remember, velocity is the vector counterpart of speed and includes direction. - It’s important to remember that while both displacement and distance measure how far an object has moved, only displacement includes direction, making it a vector. ### Revision Summary - **Scalars** have magnitude only (e.g., temperature, speed, time). - **Vectors** have both magnitude and direction (e.g., displacement). - Displacement is the only vector quantity among the options provided. - Always differentiate between speed (scalar) and velocity (vector) to avoid confusion.