Question

why does light have momentum

Answer 1

When light bounces off an object it does impart momentum to it. In the simplest case, light bouncing off a very massive stationary object, the light imparts no energy to the object. The momentum imparted is twice that of the incoming light, since it just changes directions and thus changes the sign of its momentum.

Answer 2

Answer:

When light bounces off an object it does impart momentum to it. In the simplest case, light bouncing off a very massive stationary object, the light imparts no energy to the object. The momentum imparted is twice that of the incoming light, since it just changes directions and thus changes the sign of its momentum