Can instantaneous velocity ever be negative?

Instantaneous velocity in definition is the average velocity in given particular moment time. Hence, it underlies the context of each velocity at each occupied time and space at that particular moment where you are. Moreover, talking about velocity is vector quantity, which means it both has magnitude and direction. Furthermore, this positive and negative sign attributed to their number means only the specific direction in which the object is going. For example in analogy to average velocity, the initial position of the object at the moment is 2 m/s to the right then the object suddenly changes his position to 3 m/s to the left as his final position. Which is, the exact opposite of the former direction then indicates that the final position is negative, contrary to the initial direction. Just remember that the negative values connoted on the numbers can indicate the opposite direction of either the initial position or an object is downward.

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.