Multiplication of a vector by a positive scalar quantity1) changes the direction of the vector, but not the magnitude.2) changes the magnitude of the vector, and the direction.3) changes neither the magnitude of the vector, nor the direction.4) changes the magnitude of the vector, but not the direction.
When a positive scaler is multiplied by a vector changes only the magnitude of vector but not the direction of the vector. Therefore, option (4) is correct.
