You will remember from the previous course titled 'Propagation and transmission of light', that the reason you can see non-luminous objects is because light from a light source e.g. sun or a light bulb is reflected off the non-luminous object.
The reflection of light occurs when a light ray bounces off an object. A good example is when light rays strike a smooth, polished surface like a mirror. These rays are not transmitted or absorbed, they bounce back and a reflection occurs. These light rays are referred to as reflected light rays.
The light rays that strike the surface are referred to as incident light rays.
Image: MaxPixel (PD)