What are Scalar and Vector Quantities? 
♦ On the basis of direction and magnitude physical quantities are categorized into two groups. they are .. • 1. Scalar Quantity • 2. Vector Quantities 
♦ Scalar Quantity ◘ A Scalar quantity is a quantity that has _ • Only magnitude. • But no Direction◘ Example • Temperature • Distance • Energy • Speed • Power • Density • Volume • Time • Mass • Electric Current • Charge • Pressure • Work • Specific Heat • Frequency 
♦ Vector Quantity ◘ A vector quantity is a quantity that has _ • Both a magnitude and a direction. • It follows the vector algebra rules for the performance of operations. e.g – triangle law or parallelogram law of vector addition.◘ Example : • Velocity • Displacement • Impulse • Magnetic Field • Current density • Electric Field • Momentum • Weight • Force • Acceleration • Angular velocity 
How to represent Scalar and Vector quantity◘ Scalar Quantity ◘ Examples ◘ Vector Quantity • A vector quantity denoted by – Bold face letter or symbol • A vector is also represented by a bar or an arrow placed over the letter. • Example of physical quantities that are represented by vectors are …. • The magnitude of a vector is also represented by modulas function. 
Difference between Scalar and Vector quantities 

Scalar  Vector 

It has only magnitude, but no direction.  It has both magnitude and direction. 
Scalar quantity can divide another scalar quantity  Two vector quantities cannot be divided. 
Every scalar quantity is one dimensional.  Vector quantity can be one (e.g UnitVector), two(e.g Force) or three dimensional (e.g Impuls). 
Any changes in scalar quantity only affects the magnitude of the quantity.  Any Changes in vector quantity may affect the magnitude or direction of the vector or both magnitude and direction may affected . 
It follows the ordinary algebraic rules like addition, multiplication and subtraction  It follows the vector algebra rules for the performance of operations. 
Similarities between Scalar and Vector Quantities 
• A certain physical quantity is represented by both scalar and vector quantity. • Both have a specific dimension and unit. • By using a suitable instrument we can measure both the quantities. • Both the quantity holds a certain finite magnitude. • Both scalar and vector quantities can be represented by a numerical magnitude corresponding unit. 
♦ More Related Topics • Units and Measurements • Units / System of Units 