If, for example, light knocks the extra electron off a free, negatively charged bromine molecule, Br2-, thelectronof of course escapes.
The traditional way of measuring this is to shine a light on a chunk of the solid material: The light knocks electrons out of the solid, and their energy, momentum and spin can be measured once they are ejected.
Shining sunlight onto silicon is the most direct way of turning it into electricity (the light knocks electrons free from the silicon atoms), but it is also the most expensive.
They discovered how to use the photoelectric effect, in which a photon of light knocks an electron out of its orbital around an atom, to make devices that, if laid out in an array, could record an image.
The chemicals are hydroxyl radicals, which are created as ultraviolet light knocks hydrogen atoms from water molecules in air in the presence of ozone, a highly reactive form of oxygen.
In doing so, he was struck by a beam of light knocking him to the ground unconscious.
It's solid-feeling and heavy, too, both of which point to a quality of build and design that should stand up to some light knocking about, too.
Newton suggested that light knocks away water particles from fluid-filled pores of the plant and "by this meanes juices continually arise up from the roots of trees upward," he wrote.
A time Or two had my lights knocked out, my knee socks knocked off, But soft.
