Nonspecific fever. Kids infected with coxsackievirus usually establish an unexpected fever that lasts about 3 days. Often the fever comes in two waves â it is there for a day or two, disappears for a couple of days, then returns for about 3 days.
Albert Einstein proposed the idea the light exists of quanta of energy that he called photons.
Einstein called these energy packets photons, and these are now recognised as a fundamental particle. Visible light is carried by photons, and so are all the other kinds of electromagnetic radiation like X-rays, microwaves and radio waves. In other words, light is a particle.