4 facts about light waves

Ray of light travels very fast. The speed of light in space is approximately 300 million metres per second. Light is a kind of energy that can move in waves and it is made up of a flow of small particles of energy called photons. A ray of light travels very fast.

In the graph, the vertex of the parabola hits point (-1,-2). Therefore, the axis of symmetry is x = -1. It is not y = -2, since the parabola opens vertically, not horizontally.