The correct option is **C. Temperature**. ### Explanation of Why the Answer is Correct 1. **Definition of Scalars and Vectors**: - **Scalars** are quantities that are fully described by a magnitude (numerical value) alone. They do not have a direction associated with them. - **Vectors**, on the other hand, are quantities that have both a magnitude and a direction. 2. **Analysis of Each Option**: - **A. Displacement**: Displacement is a vector quantity. It measures the change in position of an object and is defined by both the distance moved and the direction of that movement. For example, if you move 5 meters to the east, your displacement is 5 meters east. - **B. Velocity**: Velocity is also a vector quantity. It describes the rate of change of displacement and includes both speed (magnitude) and direction. For instance, if a car is moving at 60 km/h to the north, its velocity is 60 km/h north. - **C. Temperature**: Temperature is a scalar quantity. It is measured in degrees (Celsius, Fahrenheit, Kelvin) and only has a magnitude. For example, saying the temperature is 25 degrees Celsius does not involve any direction; it simply indicates how hot or cold something is. - **D. Acceleration**: Acceleration is a vector quantity as well. It measures the rate of change of velocity and includes both magnitude and direction. For example, if a car accelerates at 3 m/s² to the south, that indicates both how fast it is speeding up and the direction of that change. ### Why the Other Options are Wrong or Weaker - **Displacement (A)**: As explained, displacement involves direction, making it a vector. This is a fundamental distinction that categorizes it as a vector quantity. - **Velocity (B)**: Similar to displacement, velocity includes both speed and direction. This dual nature is what classifies it as a vector, making it unsuitable as a scalar. - **Acceleration (D)**: Acceleration also has both magnitude and direction, which is why it is classified as a vector. It describes how quickly an object is speeding up or slowing down in a specific direction. ### Common Pitfalls - **Confusing Scalars and Vectors**: A common mistake is to confuse scalar quantities with vector quantities. Remember that scalars have no direction, while vectors do. - **Misunderstanding Units**: Sometimes students may think that because a quantity has a unit (like degrees for temperature), it must be a vector. However, the key is whether or not the quantity has a directional component. ### Summary for Revision - Scalars are quantities described only by magnitude (e.g., temperature). - Vectors are quantities described by both magnitude and direction (e.g., displacement, velocity, acceleration). - Temperature is a scalar because it does not involve direction. - Always check if a quantity has a directional component to determine if it is a scalar or vector.